(中文版)平狄克微观经济学全部课后答案
平狄克《微观经济学》课后答案 18
CHAPTER 18EXTERNALITIES AND PUBLIC GOODSThis chapter extends the discussion of market failure begun in Chapter 17. To avoid over-emphasis on definitions, stress the main theme of the chapter: the characteristics of some goods lead to situations where price is not equal to marginal cost. Rely on the discussion of market power (Chapter 10) as an example of market failure. Also, point out with each case that government intervention might not be required if property rights can be defined and transaction costs are small (Section 18.3). The first four sections present positive and negative externalities and solutions to market failure. The last two sections discuss public goods and public choice.The consumption of many goods involves the creation of externalities. Stress the divergence between social and private costs. Exercise (5) presents the classic beekeeper/apple-orchard problem, originally popularized in Meade, “External Economies and Diseconomies in a Competitive Situation,” Economic Journal (March 1952). Empirical research on this example has shown that beekeepers and orchard owners have solved many of their problems: see Cheung, “The Fable of the Bees: An Economic Investigation,” Journal of Law and Economics (April 1973).Solutions to the problems of externalities are presented in Sections 18.2 and 18.3. Section 18.2, in particular, discusses emission standards, fees, and transferable permits. Example 18.1 and Exercise (3) are simple applications of these concepts.One of the main themes of the law and economics literature since 1969 is the application of Coase’s insight on the assignment of property rights. The original article is clear and can be understood by students. Stress the problems posed by transactions costs. For a lively debate, ask students whether non-smokers should be granted the right to smokeless air in public places (see Exercise (4)). For an extended discussion of the Coase Theorem at the undergraduate level, see Polinsky, Chapters 3-6, An Introduction to Law & Economics (Little, Brown & Co., 1983).The section on common property resources emphasizes the distinction between private and social marginal costs. Example 18.5 calculates the social cost of unlimited access to common property, and the information provided is used in Exercise (7). Exercise (8) provides an extended example of managing common property.The last two sections focus on public goods and private choice. Point out the similarities and differences between public goods and other activities with externalities. Since students confuse nonrival and nonexclusive goods, create a table similar to the following and give examples to fill in the cells:The next stumbling block for students is achieving an understanding of why we add individual demand curves vertically rather than horizontally. Exercise (6) compares vertical and horizontal summation of individual demand.The presentation of public choice is a limited introduction to the subject, but you can easily expand on this material. A logical extension of this chapter is an introduction to cost-benefit analysis. For applications of this analysis, see Part III, “Empirical Analysis of Policies and Programs,” in Haveman and Margolis (eds.), Public Expenditure and Policy Analysis (Houghton Mifflin, 1983).1. Which of the following describes an externality and which does not? Explain the difference.a. A policy of restricted coffee exports in Brazil causes the U.S. price of coffee to rise,which in turn also causes the price of tea to increase.Externalities cause market inefficiencies by preventing prices from conveying accurateinformation. A policy of restricting coffee exports in Brazil causes the U.S. price ofcoffee to rise, because supply is reduced. As the price of coffee rises, consumers switchto tea, thereby increasing the demand for tea, and hence, increasing the price of tea.These are market effects, not externalities.b. An advertising blimp distracts a motorist who then hits a telephone pole.An advertising blimp is producing information by announcing the availability of somegood or service. However, its method of supplying this information can be distractingfor some consumers, especially those consumers who happen to be driving neartelephone poles. The blimp is creating a negative externality that influences thedrivers’ safety. Since the price charged by the advertising firm does not incorporate theexternality of distracting drivers, too much of this type of advertising is produced fromthe point of view of society as a whole.2. Compare and contrast the following three mechanisms for treating pollution externalities when the costs and benefits of abatement are uncertain: (a) an emissions fee, (b) an emissions standard, and (c) a system of transferable emissions permits.Since pollution is not reflected in the marginal cost of production, its emission createsan externality. Three policy tools can be used to reduce pollution: an emissions fee, anemissions standard, and a system of transferable permits. The choice between a feeand a standard will depend on the marginal cost and marginal benefit of reducingpollution. If small changes in abatement yield large benefits while adding little to cost,the cost of not reducing emissions is high. Thus, standards should be used. However, ifsmall changes in abatement yield little benefit while adding greatly to cost, the cost ofreducing emissions is high. Thus, fees should be used.A system of transferable emissions permits combines the features of fees and standardsto reduce pollution. Under this system, a standard is set and fees are used to transferpermits to the firm that values them the most (i.e., a firm with high abatement costs).However, the total number of permits can be incorrectly chosen. Too few permits willcreate excess demand, increasing price and inefficiently diverting resources to ownersof the permits. Typically, pollution control agencies implement one of threemechanisms, measure the results, reassess the success of their choice, then reset newlevels of fees or standards or select a new policy tool.3. When do externalities require government intervention, and when is such intervention unlikely to be necessary?Economic efficiency can be achieved without government intervention when theexternality affects a small number of people and when property rights are wellspecified. When the number of parties is small, the cost of negotiating an agreementamong the parties is small. Further, the amount of required information (i.e., the costsof and benefits to each party) is small. When property rights are not well specified,uncertainty regarding costs and benefits increases and efficient choices might not bemade. The costs of coming to an agreement, including the cost of delaying such anagreement, could be greater than the cost of government intervention, including theexpected cost of choosing the wrong policy instrument.4. An emissions fee is paid to the government, whereas an injurer who is sued and is held liable pays damages directly to the party harmed by an externality. What differences in the behavior of victims might you expect to arise under these two arrangements?When the price of an activity that generates an externality reflects social costs, anefficient level of the activity is maintained. The producer of the externality reduces (fornegative externalities) or increases (for positive externalities) activity away from(towards) efficient levels. If those who suffer from the externality are not compensated,they find that their marginal cost is higher (for negative externalities) or lower (forpositive externalities), in contrast to the situation in which they would be compensated.5. Why does free access to a common property resource generate an inefficient outcome?Free access to a resource means that the marginal cost to the user is less than the socialcost. The use of a common property resource by a person or firm excludes others fromusing it. For example, the use of water by one consumer restricts its use by another.Because private marginal cost is below social marginal cost, too much of the resource isconsumed by the individual user, creating an inefficient outcome.6. Public goods are both nonrival and nonexclusive. Explain each of these terms and state clearly how they differ from each other.A good is nonrival if, for any level of production, the marginal cost of providing the goodto an additional consumer is zero (although the production cost of an additional unitcould be greater than zero). A good is nonexclusive if it is impossible or very expensiveto exclude individuals from consuming it. Public goods are nonrival and nonexclusive.Commodities can be (1) exclusive and rival, (2) exclusive and nonrival, (3) nonexclusiveand rival, or (4) nonexclusive and nonrival. Most of the commodities discussed in thetext to this point have been of the first type. In this chapter, we focus on commodities ofthe last type.Nonrival refers to the production of a good or service for one more customer. It usuallyinvolves a production process with high fixed costs, such as the cost of building ahighway or lighthouse. (Remember that fixed cost depends on the period underconsideration: the cost of lighting the lamp at the lighthouse can vary over time, butdoes not vary with the number of consumers.) Nonexclusive refers to exchange, wherethe cost of charging consumers is prohibitive. Incurring the cost of identifyingconsumers and collecting from them would result in losses. Some economists focus onthe nonexclusion property of public goods because it is this characteristic that poses themost significant problems for efficient provision.7. Public television is funded in part by private donations, even though anyone with a television set can watch for free. Can you explain this phenomenon in light of the free rider problem?The free-rider problem refers to the difficulty of excluding persons from consuming anonexclusive commodity. Non-paying consumers can “free-ride” on commoditiesprovided by paying customers. Public television is funded in part by contributions.Some viewers contribute, but most watch without paying, hoping that someone else willpay so they will not. To combat this problem these stations (1) ask consumers to assesstheir true willingness to pay, then (2) ask consumers to contribute up to this amount,and (3) attempt to make everyone else feel guilty for free-riding.8. Explain why the median voter outcome need not be efficient when majority rule voting determines the level of public spending.The median voter is the citizen with the middle preference: half the voting population ismore strongly in favor of the issue and half is more strongly opposed to the issue.Under majority-rule voting, where each citizen’s vote is weighted equally, the preferredspending level on public-goods provision of the median voter will win an electionagainst any other alternative.However, majority rule is not necessarily efficient, because it weights each citizen’spreferences equally. For an efficient outcome, we would need a system that measuresand aggregates the willingness to pay of those citizens consuming the public good.Majority rule is not this system. However, as we have seen in previous chapters,majority rule is equitable in the sense that all citizens are treated equally. Thus, weagain find a trade-off between equity and efficiency.1. A number of firms located in the western portion of a town after single-family residences took up the eastern portion. Each firm produces the same product and, in the process, emits noxious fumes that adversely affect the residents of the community.a. Why is there an externality created by the firms?Noxious fumes created by firms enter the utility function of residents. We can assumethat the fumes decrease the utility of the residents (i.e., they are a negative externality)and lower property values.b. Do you think that private bargaining can resolve the problem with the externality?Explain.If the residents anticipated the location of the firms, housing prices should reflect thedisutility of the fumes; the externality would have been internalized by the housingmarket in housing prices. If the noxious fumes were not anticipated, privatebargaining could resolve the problem of the externality only if there are a relativelysmall number of parties (both firms and families) and property rights are well specified.Private bargaining would rely on each family’s willingness to pay for air quality, buttruthful revelation might not be possible. All this will be complicated by theadaptability of the production technology known to the firms and the employmentrelations between the firms and families. It is unlikely that private bargaining willresolve the problem.c. How might the community determine the efficient level of air quality?The community could determine the economically efficient level of air quality byaggregating the families’ willingne ss to pay and equating it with the marginal cost ofpollution reduction. Both steps involve the acquisition of truthful information.2. A computer programmer lobbies against copyrighting software. He argues that everyone should benefit from innovative programs written for personal computers and that exposure to a wide variety of computer programs will inspire young programmers to create even more innovative programs. Considering the marginal social benefits possibly gained by his proposal, do you agree with the programmer’s position?Computer software as information is a classic example of a public good. Since it can becostlessly copied, the marginal cost of providing software to an additional user is nearzero. Therefore, software is nonrival. (The fixed costs of creating software are high, butthe variable costs are low.) Furthermore, it is expensive to exclude consumers fromcopying and using software because copy protection schemes are available only at highcost or high inconvenience to users. Therefore, software is also nonexclusive. As bothnonrival and nonexclusive, computer software suffers the problems of public goodsprovision: the presence of free-riders makes it difficult or impossible for markets toprovide the efficient level of software. Rather than regulating this market directly, thelegal system guarantees property rights to the creators of software. If copyrightprotection were not enforced, it is likely that the software market would collapse.Therefore, we do not agree with the computer programmer.3. Four firms located at different points on a river dump various quantities of effluent into it. The effluent adversely affects the quality of swimming for homeowners who live downstream. These people can build swimming pools to avoid swimming in the river, and firms can purchase filters that eliminate harmful chemicals in the material that is dumped in the river. As a policy advisor for a regional planning organization, how would you compare and contrast the following options for dealing with the harmful effect of the effluent:a. An equal-rate effluent fee on firms located on the river.First, one needs to know the value to homeowners of swimming in the river. Thisinformation can be difficult to obtain, because homeowners will have an incentive tooverstate this value. As an upper boundary, if there are no considerations other thanswimming, one could use the cost of building swimming pools, either a pool for eachhomeowner or a public pool for all homeowners. Next, one needs to know the marginalcost of abatement. If the abatement technology is well understood, this informationshould be readily obtainable. If the abatement technology is not understood, anestimate based on the firms’ knowledge must be used.The choice of a policy tool will depend on the marginal benefits and costs of abatement.If firms are charged an equal-rate effluent fee, the firms will reduce effluents to thepoint where the marginal cost of abatement is equal to the fee. If this reduction is nothigh enough to permit swimming, the fee could be increased. Alternatively, revenuefrom the fees could be to provide swimming facilities, reducing the need for effluentreduction.b. An equal standard per firm on the level of effluent each firm can dump.Standards will be efficient only if the policy maker has complete information regardingthe marginal costs and benefits of abatement. Moreover, the standard will notencourage firms to reduce effluents further when new filtering technologies becomeavailable.c. A transferable effluent permit system, in which the aggregate level of effluent isfixed and all firms receive identical permits.A transferable effluent permit system requires the policy maker to determine theefficient effluent standard. Once the permits are distributed and a market develops,firms with a higher cost of abatement will purchase permits from firms with lowerabatement costs. However, unless permits are sold initially, rather than merelydistributed, no revenue will be generated for the regional organization.4. Recent social trends point to growing intolerance of smoking in public areas. Many people point out the negative effects of “second hand” smoke. If you are a smoker and you wish to continue smoking despite tougher anti smoking laws, describe the effect of the following legislative proposals on your behavior. As a result of these programs, do you, the individual smoker, benefit? Does society benefit as a whole?Since smoking in public areas is similar to polluting the air, the programs proposedhere are similar to those examined for air pollution. A bill to lower tar and nicotinelevels is similar to an emissions standard, and a tax on cigarettes is similar to anemissions fee. Requiring a smoking permit is similar to a system of emissions permits,assuming that the permits would not be transferable. The individual smoker in all ofthese programs is being forced to internalize the externality of “second-hand” smokeand will be worse off. Society will be better off if the benefits of a particular proposaloutweigh the cost of implementing that proposal. Unfortunately, the benefits ofreducing second-hand smoke are uncertain, and assessing those benefits is costly.a. A bill is proposed that would lower tar and nicotine levels in all cigarettes.The smoker will most likely try to maintain a constant level of consumption of nicotine,and will increase his or her consumption of cigarettes. Society may not benefit fromthis plan if the total amount of tar and nicotine released into the air is the same.b. A tax is levied on each pack of cigarettes sold.Smokers might turn to cigars, pipes, or might start rolling their own cigarettes. Theextent of the effect of a tax on cigarette consumption depends on the elasticity ofdemand for cigarettes. Again, it is questionable whether society will benefit.c. Smokers would be required to carry smoking permits at all times. These permitswould be sold by the government.Smoking permits would effectively transfer property rights to clean air from smokers tonon-smokers. The main obstacle to society benefiting from such a proposal would bethe high cost of enforcing a smoking permits system.5. A beekeeper lives adjacent to an apple orchard. The orchard owner benefits from thebees because each hive pollinates about one acre of apple trees. The orchard owner pays nothing for this service, however, because the bees come to the orchard without his having to do anything. There are not enough bees to pollinate the entire orchard, and the orchard owner must complete the pollination by artificial means, at a cost of $10 per acre of trees.Beekeeping has a marginal cost of MC = 10 + 2Q, where Q is the number of beehives.Each hive yields $20 worth of honey.a. How many beehives will the beekeeper maintain?The beekeeper maintains the number of hives that maximizes profits, when marginalrevenue is equal to marginal cost. With a constant marginal revenue of $20 (there is noinformation that would lead us to believe that the beekeeper has any market power)and a marginal cost of 10 + 2Q:20 = 10 + 2Q, or Q = 5.b. Is this the economically efficient number of hives?If there are too few bees to pollinate the orchard, the farmer must pay $10 per acre forartificial pollination. Thus, the farmer would be willing to pay up to $10 to thebeekeeper to maintain each additional hive. So, the marginal social benefit, MSB, ofeach additional hive is $30, which is greater than the marginal private benefit of $20.Assuming that the private marginal cost is equal to the social marginal cost, we setMSB = MC to determine the efficient number of hives:30 = 10 + 2Q, or Q = 10.Therefore, the beekeeper’s private choice of Q = 5 is not the socially efficient number ofhives.c. What changes would lead to the more efficient operation?The most radical change that would lead to more efficient operations would be themerger of the farmer’s business with the beekeeper’s business. This merger wouldinternalize the positive externality of bee pollination. Short of a merger, the farmerand beekeeper should enter into a contract for pollination services.7. Reconsider the common resource problem as given by Example 18.5. Suppose that crawfish popularity continues to increase, and that the demand curve shifts from C = 0.401 - 0.0064F to C = 0.50 - 0.0064F. How does this shift in demand affect the actual crawfish catch, the efficient catch, and the social cost of common access? (Hint: Use the marginal social cost and private cost curves given in the example.)The relevant information is now the following:Demand: C = 0.50 - 0.0064FMSC: C = -5.645 + 0.6509F.With an increase in demand, the demand curve for crawfish shifts upward, intersectingthe price axis at $0.50. The private cost curve has a positive slope, so additional effortmust be made to increase the catch. Since the social cost curve has a positive slope, thesocially efficient catch also increases. We may determine the socially efficient catch bysolving the following two equations simultaneously:0.50 - 0.0064F = -5.645 + 0.6509F, or F* = 9.35.To determine the price that consumers are willing to pay for this quantity, substituteF* into the equation for marginal social cost and solve for C:C = -5.645 + (0.6509)(9.35), or C = $0.44.Next, find the actual level of production by solving these equations simultaneously:Demand: C = 0.50 - 0.0064FMPC: C = -0.357 + 0.0573F0.50 - 0.0064F = -0.357 + 0.0573F, or F** = 13.45.To determine the price that consumers are willing to pay for this quantity, substituteF** into the equation for marginal private cost and solve for C:C = -0.357 + (0.0573)(13.45), or C = $0.41.Notice that the marginal social cost of producing 13.45 units isMSC = -5.645 +(0.6509)(13.45) = $3.11.With the increase in demand, the social cost is the area of a triangle with a base of 4.1million pounds (13.45 - 9.35) and a height of $2.70 ($3.11 - 0.41), or $5,535,000 morethan the social cost of the original demand.8. The Georges Bank, a highly productive fishing area off New England, can be divided into two zones in terms of fish population. Zone 1 has the higher population per square mile but is subject to severe diminishing returns to fishing effort. The daily fish catch (in tons) in Zone 1 isF 1 = 200(X1) - 2(X1) 2where X1is the number of boats fishing there. Zone 2 has fewer fish per mile but is larger, and diminishing returns are less of a problem. Its daily fish catch isF 2 = 100(X2) - (X2) 2where X2is the number of boats fishing in Zone 2. The marginal fish catch MFC in each zone can be represented asMFC1 = 200 - 4(X1) MFC2= 100 - 2(X2).There are 100 boats now licensed by the U.S. government to fish in these two zones. The fish are sold at $100 per ton. The total cost (capital and operating) per boat is constant at $1,000 per day. Answer the following questions about this situation.a. If the boats are allowed to fish where they want, with no government restriction,how many will fish in each zone? What will be the gross value of the catch?Without restrictions, the boats will divide themselves so that the average catch (AF 1and AF 2) for each boat is equal in each zone. (If the average catch in one zone is greaterthan in the other, boats will leave the zone with the lower catch for the zone with thehigher catch.) We solve the following set of equations:AF 1 = AF 2 and X 1 + X 2 = 100 where 11121120022002AF X X X X =-=- and 222222100100AF X X X X =-=-. Therefore, AF 1 = AF 2 implies200 - 2X 1 = 100 - X 2,200 - 2(100 - X 2) = 100 - X 2, or X 21003= and 320031001001=⎪⎭⎫ ⎝⎛-=X . Find the gross catch by substituting the value of X 1 and X 2 into the catch equations:()(),,,,F 444488983331332002320020021=-=⎪⎭⎫ ⎝⎛-⎪⎭⎫ ⎝⎛= and ().,,,F 2222111133333100310010022=-=⎪⎭⎫ ⎝⎛-⎪⎭⎫ ⎝⎛= The total catch is F 1 + F 2 = 6,666. At the price of $100 per ton, the value of the catch is$666,600. The average catch for each of the 100 boats in the fishing fleet is 66.66 tons.To determine the profit per boat, subtract total cost from total revenue:π = (100)(66.66) - 1,000, or π = $5,666.Total profit for the fleet is $566,000.b. If the U.S. government can restrict the boats, how many should be allocated to eachzone? What will the gross value of the catch be? Assume the total number of boats remains at 100.Assume that the government wishes to maximize the net social value of the fish catch,i.e., the difference between the total social benefit and the total social cost. Thegovernment equates the marginal fish catch in both zones, subject to the restrictionthat the number of boats equals 100:MFC 1 = MFC 2 and X 1 + X 2 = 100,MFC 1 = 200 - 4X 1 and MFC 2 = 100 - 2X 2.Setting MFC 1 = MFC 2 implies:200 - 4X 1 = 100 - 2X 2, or 200 - 4(100 - X 2) = 100 - 2X 2, or X 2 = 50 andX 1 = 100 - 50 = 50.Find the gross catch by substituting X 1 and X 2 into the catch equations:F 1 = (200)(50) - (2)(502) = 10,000 - 5,000 = 5,000 andChapter 18: Externalities and Public Goods242 F 2 = (100)(50) - 502 = 5,000 - 2,500 = 2,500.The total catch is equal to F 1 + F 2 = 7,500. At the market price of $100 per ton, thevalue of the catch is $750,000. Total profit is $650,000. Notice that the profits are notevenly divided between boats in the two zones. The average catch in Zone A is 100 tonsper boat, while the average catch in Zone B is 50 tons per boat. Therefore, fishing inZone A yields a higher profit for the individual owner of the boat.c. If additional fishermen want to buy boats and join the fishing fleet, should agovernment wishing to maximize the net value of the fish catch grant them licenses to do so? Why or why not?To answer this question, first determine the profit-maximizing number of boats in eachzone. Profits in Zone A areππA A X X X X X =--=-1002002100019000200112112b g e j,,, or . To determine the change in profit with a change in X 1 take the first derivative of theprofit function with respect to X 1:d dX X A π1119000400=-,. To determine the profit-maximizing level of output, setd dX A π1equal to zero and solve for X 1:19,000 - 400X 1 = 0, or X 1 = 47.5.Substituting X 1 into the profit equation for Zone A gives: ()()()()()()()()250,451$5.47000,15.4725.472001002=--=A π.For Zone B follow a similar procedure. Profits in Zone B areππB B X X X X X =--=-100100100090002002222222b g e j,,, or . Taking the derivative of the profit function with respect to X 2 givesd X B π229000200=-,. Setting d B π2equal to zero to find the profit-maximizing level of output gives 9,000 - 200X 2 = 0, or X 2 = 45.Substituting X 2 into the profit equation for Zone B gives:πB = (100)((100)(45) - 452) - (1,000)(45) = $202,500.Total profit from both zones is $653,750, with 47.5 boats in Zone A and 45 boats in ZoneB. Because each additional boat above 92.5 decreases total profit, the governmentshould not grant any more licenses.。
平狄克第八版课后答案
平狄克第八版课后答案【篇一：平狄克微观经济学课后习题答案-第7-8 章】> 1. 显性成本2. 她自己做其他事时会得到的最高收入3. 多用资本,少用工人4. 完全竞争价格给定, 即斜率不变5. 不意味6. 意味着递增7. avcac mc 递增mc=avc 最低点mc=ac 最低点1.1 形9 . 长期扩展线为把等产量线簇上斜率相同点连起来,此时它改变了斜率10 .规模经济基础是内在经济,针对一种产品范围经济基础是同时生产高度相关的产品.练习题1.avc=1000 ac=1000+1000/q非常大,最后为10002. 不对,除非工人只可以在这里找到工作3. 见书后4. 见书后5. 见书后6. 每个均衡点斜率更小7. 不同意,应按不同时段定价,如不可,则同意8. 见书后9.tc=120000+3000(q/40)+2000ac=75+122000/qmc=75ac 随q 减小2 个劳动组,1600 元1/4, 更大的生产能力11.190 万元53 元53 元19 元第七章附录练习题1 、我们考查规模报酬时可由f( ak，al)与af( k，l)之间的关系判断当f( ak，al) af( k，l),表明是规模报酬递增；当f( ak，al) =af( k，l),表明是规模报酬不变；当f( ak，al) af( k，l),表明是规模报酬递减；( a)规模报酬递增；( b)规模报酬不变；( c)规模报酬递增。
2 、根据已知条件，资本价格r=30 ，设劳动价格为w，则成本函数c=30k+ wl联立(1) ，(2)，(3)可得k=(w/3) 1/2 ,l=(300/w) 1/2 ,此时成本最小，代入成本函数c=30k+ wl ，得c=2 ( 300w ) 1/2联立(1) ，(2)，(3)可得k/l=3/4 ,此时成本最小，即生产既定产出的成本最小化的资本和劳动的组合为资本/劳动=3/4。
4、( a)已知q=10k0.8(l-40)0.2 ,得mpl=2(k/ (l-40))0.8 , mpk=8( (l-40) / k)0.2 ,在最小成本点有：mpl/ mpk=w/r即2(k/ (l-40))0.8/8( (l-40) / k)0.2=w/r ，k/( l-40) =4 w/r ，l-40=kr/4w ，0.80.20.2q=10k(l-40)=10 k ( r/4w)，最小需求为:k=q/10(r/4w)0.2 ，l=40+ q (r/4w)0.8/10总成本函数为：tc=10q+kr+lw=10q+q/10((4w)0.2r0.8+(r/4)0.8w0.2)+40w( b)当r=64 ，w=32 时tc=10q+ (2*20.2+0.50.8)32 q/10+1280tc=1280+10q+91.84 q/10=1280+19.184q该技术呈现规模递减。
平狄克微观经济学第九本课后习题答案笔记
平狄克微观经济学第九版课后习题答案与笔记内容简介本书遵循平狄克《微观经济学》（第9版）教材的章⽬目编排，共分4篇19章，每章由三部分组成：第⼀一部分为复习笔记，总结本章的重难点内容；第⼆二部分为课（章）后复习题详解，对第9版的所有课（章）后复习题都进⾏行行了了详细的分析和解答；第三部分为课（章）后练习题详解，对第9版的所有课（章）后练习题都进⾏行行了了详细的分析和解答。
作为该教材的学习辅导书，本书具有以下⼏几个⽅方⾯面的特点：（1）整理理名校笔记，浓缩内容精华。
每章的复习笔记以平狄克所著的《微观经济学》（第9版）为主，并结合国内外其他微观经济学经典教材对各章的重难点进⾏行行了了整理理，因此，本书的内容⼏几乎浓缩了了经典教材的知识精华。
（2）解析课后习题，提供详尽答案。
本书参考⼤大量量经济学相关资料料对平狄克所著的《微观经济学》（第9版）的课（章）后习题进⾏行行了了详细的分析和解答，并对相关重要知识点进⾏行行了了延伸和归纳。
（3）补充相关要点，强化专业知识。
⼀一般来说，国外英⽂文教材的中译本不不太符合中国学⽣生的思维习惯，有些语⾔言的表述不不清或条理理性不不强⽽而给学习带来了了不不便便，因此，对每章复习笔记的⼀一些重要知识点和⼀一些习题的解答，我们在不不违背原书原意的基础上结合其他相关经典教材进⾏行行了了必要的整理理和分析。
⽬目录第1篇 导论：市场与价格 第1章 绪 论 1.1 复习笔记 1.2 课后复习题详解 1.3 课后练习题详解 第2章 供给与需求的基本原理 2.1 复习笔记 2.2 课后复习题详解 2.3 课后练习题详解第2篇 ⽣产者、消费者与竞争性市场 第3章 消费者⾏为 3.1 复习笔记 3.2 课后复习题详解 3.3 课后练习题详解 第4章 个⼈需求与市场需求 4.1 复习笔记 4.2 课后复习题详解 4.3 课后练习题详解 第4章附录 需求理论：⼀种数学的处理⽅法 第5章 不确定性与消费者⾏为 5.1 复习笔记 5.2 课后复习题详解 5.3 课后练习题详解 第6章 ⽣ 产 6.1 复习笔记 6.2 课后复习题详解 6.3 课后练习题详解 第7章 ⽣产成本 7.1 复习笔记 7.2 课后复习题详解 7.3 课后练习题详解 第7章附录 ⽣产与成本理论：⼀种数学的处理⽅法 第8章 利润最⼤化与竞争性供给 8.1 复习笔记 8.2 课后复习题详解 第9章 竞争性市场分析 9.1 复习笔记 9.2 课后复习题详解 9.3 课后练习题详解第3篇 市场结构与竞争策略 第10章 市场势⼒：垄断与买⽅垄断 10.1 复习笔记 10.2 课后复习题详解 10.3 课后练习题详解 第11章 有市场势⼒的定价 11.1 复习笔记 11.2 课后复习题详解 11.3 课后练习题详解 第11章附录 纵向联合⼚商 第12章 垄断竞争与寡头垄断 12.1 复习笔记 12.2 课后复习题详解 12.3 课后练习题详解 第13章 博弈论与竞争策略 13.1 复习笔记 13.2 课后复习题详解 13.3 课后练习题详解 第14章 投⼊要素市场 14.1 复习笔记 14.2 课后复习题详解 14.3 课后练习题详解 第15章 投资、时间与资本市场 15.1 复习笔记 15.2 课后复习题详解第4篇 信息、市场失灵与政府的⾓⾊ 第16章 ⼀般均衡与经济效率 16.1 复习笔记 16.2 课后复习题详解 16.3 课后练习题详解 第17章 信息不对称的市场 17.1 复习笔记 17.2 课后复习题详解 17.3 课后练习题详解 第18章 外部性与公共物品 18.1 复习笔记 18.2 课后复习题详解 18.3 课后练习题详解 第19章 ⾏为经济学 19.1 复习笔记 19.2 课后复习题详解 19.3 课后练习题详解附录 指定平狄克《微观经济学》教材为考研参考书⽬目的院校列列表1.2. 课后习题详解1 ⼈人们常说，⼀一个好的理理论是可以⽤用实证的、数据导向的研究来加以证伪的。
平狄克微观经济学答案第10-Word文档
第十章 复习题1．该垄断者减少产量，直到边际成本等于边际收益。
2．P MC P E D-=-1该等式表明，当弹性上升（需求变得更加有弹性），弹性相反数的下降和度量市场力的下降，因而当弹性上升（下降），厂商有更少（多）能力使价格高于边际成本。
3．垄断者的产出决定由需求曲线和边际成本决定。
因而需求的变动不仅像竞争的供给曲线那样给出一系列价格和产量，而且需求的变动可以导致价格改变但产量并不变，也可以导致产量改变而价格不变。
他们不存在价格和产量之间的一一对应关系，因自垄断市场没有供给曲线。
4．垄断力量的程度或一个厂商左右市场的力量取决于面对的需求曲线的弹性。
因此如果厂商的需求曲线的弹性小于无穷，厂商就有一些垄断势力。
5．来源于3个方面：（1）市场需求弹性，如，欧佩克利用石油在短期是无弹性而控制油价（2）厂商的数目，如，某3个厂商控制某一产品的市场份额，他们就有了垄断势力（3）厂商间的相互作用，如，几个主要的厂商相互串通，那么他们就能产生垄断势力。
6．同上7．垄断势力的结果是较高的价格和较低的产量，容易使消费者的利益受损,消费者剩余就会减少。
同时厂商可能用一些非生产的方式来保持他的垄断地位，从而使社会成本更大。
8． 藉由在垄断者的取利润最大值的价格下面限制价格，政府能改变厂商的边际收益曲线的形状。
当价格极高被征税的时候，边际收益为比以极高价格量低的量和极高价格相等。
如果政府取输出最大值,它应该将一个价格对手设定为边际成本。
价格在这一个水平下面引诱公司减少制造, 假定边际成本曲线正在以上难以下咽的食物。
调整者的问题要决定垄断的边际成本曲线的形状。
9. 边际的支出是在总支出方面的改变如被购买的量的变化。
对于为购买由于许多厂商竞争的一个厂商，边际的支出和平均支出相等。
所有的厂商应该购买以便最后一个单位的边际价值和在那一个单位上的边际支出相等。
这对两者的竞争买主和垄断者是真实的。
10. 买方垄断势力是购买者影响一种货物价格的能力。
平狄克《微观经济学》第七版·课后习题答案中文word资料68页
第一章复习题1．市场是通过相互作用决定一种或一系列产品价格的买卖双方的集合，因此可以把市场看作决定价格的场所。
行业是出售相同的或紧密相关的产品的厂商的集合，一个市场可以包括许多行业。
2．评价一个理论有两个步骤：首先，需要检验这个理论假设的合理性；第二，把该理论的预测和事实相比较以此来验证它。
如果一个理论无法被检验的话，它将不会被接受。
因此，它对我们理解现实情况没有任何帮助。
3．实证分析解释“是什么”的问题，而规范分析解释的是“应该是什么”的问题。
对供给的限制将改变市场的均衡。
A中包括两种分析，批评这是一种“失败的政策”——是规范分析，批评其破坏了市场的竞争性——是实证分析。
B向我们说明在燃油的配给制下总社会福利的被损坏——是实证分析。
4．由于两个市场在空间上是分离的，商品在两地间的运输是套利实现的条件。
如果运输成本为零，则可以在Oklahoma购买汽油，到New Jersey出售，赚取差价；如果这个差价无法弥补运输成本则不存在套利机会。
5．商品和服务的数量与价格由供求关系决定。
鸡蛋的实际价格从1970年至1985年的下降，一方面是由于人们健康意识的提高而导致鸡蛋需求的减少，同时也因为生产成本的降低。
在这两种因素下，鸡蛋的价格下降了。
大学教育的实际价格的升高，是由于越来越多的人倾向于获得大学教育而导致需求提高，同时教育的成本也在升高。
在这两方面因素作用下，大学教育费用提高了。
6．日圆相对美圆来说，价值升高，升值前相比，兑换同样数量的日圆需要付出更多的美圆。
由汇率的变化引起购买力的变化，在日本市场出售的美国汽车，由于美圆贬值日圆升值，持有日圆的消费者将较以前支付较底的价格；而在美国市场出售的日本汽车，由于日圆升值美圆贬值，持有美圆的消费者将面对较以前提高的价格。
第二章复习题1.假设供给曲线固定，炎热天气通常会引起需求曲线右移，在当前价格上造成短期需求过剩。
消费者为获得冰激凌，愿意为每一单位冰激凌出价更高。
平狄克《微观经济学》课后答案 17
CHAPTER 17MARKETS WITH ASYMMETRIC INFORMATIONLike Chapter 15, this chapter follows a “hub-and-spoke” pattern. The hub, found in the introduction to the chapter, defines asymmetric information. The spokes include Sections 17.1 and 17.3 on adverse selection and moral hazard Section 17.2 on signaling the principal-agent problem in Sections 17.4 and 17.5 and the efficiency wage model in Section 17.6. Although much of the discussion of these topics is conceptual, an algebraic or geometric model is presented in each section and the exercises focus on the intuition behind the models.It is best to introduce asymmetric information by reviewing where microeconomics has assumed perfect information. For example, except for Chapter 5 and sections of Chapter 15, we have assumed perfect knowledge of the future (no uncertainty). In models of uncertainty, consumers and producers play “games against nature.” In models of asymmetric information, they are playing games with each other.Many of your students are likely to have bought or sold a used car and will, therefore, find the lemons model interesting. Start your presentation by asking the sellers of used cars how they determined their asking price. Emphasize the intuition of the model before presenting Figure 17.1. If they have understood the model, they should ask a high price to give the impression to buyers that the car they are selling is of high quality. Class discussion could consider whether the government should pass laws requiring warranties in the sale of used cars.The market for insurance is also one with which most students are familiar. Although car insurance is required in many states, liability limits may vary from policy to policy. Discuss how risk-averse individuals will want to purchase policies with higher limits and how insurance companies determine the riskiness of the insurance (see Review Question (3)). If you have used the example of buying a house in Chapter 15, you may extend it here by considering how bankers determine whether borrowers will default on their home loans (see Exercise (2)).When discussing market signaling, point out the dual function of education (as training and as a signal of higher productivity). The “Simple Model of Job Market Signaling,” which is presented in Section 17.2, might confuse students unfamiliar with discontinuous functions (see Figure 17.2). Explain how educational degrees lead to discontinuities, and stress the relationship between degrees, guarantees, and warranties of educational quality. See Exercises (1) and (2) for a discussion of these issues.Moral hazard is an easy concept to illustrate with examples, but it is important to draw a clear distinction between adverse selection and moral hazard. Exercise (5) combines discussions of the lemons market, signaling, and moral hazard. Exercise (7) combines discussions of moral hazard and warranties.The principal-agent problem is presented in the context of the relationship between employer and employee. It can be generalized to the relationship between a regulator and a regulated firm and to the relationship between voters and elected officials. In discussing the problems of monitoring agents, you can reintroduce the concept of transactions costs (from Section 16.2). Monitoring costs are discussed in Review Questions (6) and (7). The most interesting topic of this section is how to design contracts to provide the proper incentives for agents to perform in the interest of the principal. The starred Section 17.5 extends this topic to managerial incentives in an integrated firm. The model can be applied to government contracts, i.e., defense contracts, for a discussion of cost-plus contracting.The shirking model of efficiency wages is conceptually difficult. After discussing efficiency in Chapter 16, students might wonder what is so efficient about paying workers a wage that is greater than the value of their marginal product. Stress the role of asymmetric information here: firms have imperfect information about individual worker productivity. If you present this model, first read the references in Footnote 17. While Yellen’s article is concise, Stiglitz’s is more general, discussing shirking on page 20 and the relationship between efficiency wage theory and unemployment on pages 33-37.1. Why can asymmetric information between buyers and sellers lead to a market failure when a market is otherwise perfectly competitive?Asymmetric information leads to market failure because the transaction price does notreflect either the marginal benefit to the buyer or the marginal cost of the seller. Thecompetitive market fails to achieve an output with a price equal to marginal cost. Insome extreme cases, if there is no mechanism to reduce the problem of asymmetricinformation, the market collapses completely.2. If the used car market is a “lemons” market, how would you expect the repair record of used cars that are sold to compare with the repair record of those not sold?In the market for used cars, the seller has a better idea of the quality of the used carthan does the buyer. The repair record of the used car is one indicator of quality. Onewould expect that, at the margin, cars with good repair records would be kept whilecars with poor repair records would be sold. Thus, one would expect the repair recordsof used cars that are to be sold to be worse than those of used cars not sold.3. Explain the difference between adverse selection and moral hazard in insurance markets. Can one exist without the other?In insurance markets, both adverse selection and moral hazard exist. Adverse selectionrefers to the self-selection of individuals who purchase insurance policies. In otherwords, people who are less risky than the insured population will, at the margin, choosenot to insure, while people more risky than the population will choose to insure. As aresult, the insurance company is left with a riskier pool of policy holders. The problemof moral hazard occurs after the insurance is purchased. Once insurance is purchased,less risky individuals might engage in behavior characteristic of more risky individuals.If policy holders are fully insured, they have little incentive to avoid risky situations.An insurance firm may reduce adverse selection, without reducing moral hazard, andvice versa. Researching to determine the riskiness of a potential customer helpsinsurance companies reduce adverse selection. Furthermore, insurance companiesreevaluate the premium (sometimes canceling the policy) when claims are madeagainst the policy, thereby reducing moral hazard. Copayments also reduce moralhazard by creating a disincentive for policy holders to engage in risky behavior.4. Describe several ways in which sellers can convince buyers that their products are of high quality. Which methods apply in the following products: Maytag washing machines, Burger King hamburgers, large diamonds?Some signal the quality of their products to buyers through (1) investment in a goodreputation, (2) the standardization of products, (3) certification (i.e., the use ofeducational degrees in the labor market), (4) guarantees, and (5) warranties. Maytagsignals the high quality of its washing machines by offering one of the best warrantiesin the market. (See Consumer Reports, February 1988, p. 82.) Burger King relies onthe standardization of its hamburgers, e.g., the Whopper. The sale of a large diamondis accompanied by a certificate that verifies the weight and shape of the stone anddiscloses any flaws.5. Why might a seller find it advantageous to signal the quality of her product? How are guarantees and warranties a form of market signaling?Firms producing high-quality products would like to charge higher prices, but to do thissuccessfully, potential consumers must be made aware of the quality differences amongbrands. One method of providing product quality information is through guarantees(i.e., the promise to return what has been given in exchange if the product is defective)and warranties (i.e., the promise to repair or replace if defective). Since low-qualityproducers are unlikely to offer costly signaling devices, consumers can correctly view aguarantee or an extensive warranty as a signal of high quality, thus confirming theeffectiveness of these measures as signaling devices.6. Why might managers of firms be able to achieve objectives other than profit maximization, the goal of the firm’s shareholders?It is difficult and costly for shareholders to constantly monitor the actions of the firm’smanagers. The firm’s owners are in a better position to engage in monitoring, butmanagers’ behaviors still cannot be scrutinized one hundred percent of the time.Therefore, managers have some leeway to pursue their own objectives.7. How can the principal-agent model be used to explain why public enterprises, such as post offices, might pursue goals other than profit maximization?The problem of overseeing a public enterprise is one of asymmetric information. Themanager (agent) is more familiar with the cost structure of the enterprise and thebenefits to the customers than the principal, an elected or appointed official, who mustelicit cost information controlled by the manager. The costs of eliciting and verifyingthe information, as well as independently gathering information on the benefitsprovided by the public enterprise, can be more than the difference between the agency’spotential net returns (“profits”) and realized returns. This difference provides room forslack, which can be distributed to the management as personal benefits, to the agency’sworkers as greater-than-efficient job security, or to the agency’s customers in the formof greater-than-efficient provision of goods or services.8. Why are bonus and profit-sharing payment schemes likely to resolve principal-agent problems, whereas a fixed wage payment will not?With a fixed wage, the agent-employee has no incentive to maximize productivity. Ifthe agent-employee is hired at a fixed wage equal to the marginal revenue product ofthe average employee, there is no incentive to work harder than the least productiveworker. Bonus and profit-sharing schemes involve a lower fixed wage than fixed-wageschemes, but they include a bonus wage. The bonus can be tied to the profitability ofthe firm to the output of the individual employee, or to that of the group in which theemployee works. These schemes provide a greater incentive for agents to maximize theobjective function of the principal.9. What is an efficiency wage? Why is it profitable for the firm to pay an efficiency wage when workers have better information about their productivity than firms do?An efficiency wage, in the context of the shirking model, is the wage at which noshirking occurs. If employers cannot monitor employees’ productivity, then employeesmay shirk (work less productively), which will affect the firm’s output and profits. Ittherefore pays the firm to offer workers a higher-than-market wage, thus reducing theworkers’ incentive to shirk, because they know that if they are fired and end upworking for another firm, their wage will fall.1. Many consumers view a well-known brand name as a signal of quality and will pay more for a brand-name product (e.g., Bayer aspirin instead of generic aspirin, Birds Eye frozen vegetables instead of the supermarket’s own brand). Can a brand name provide a useful signal of quality? Why or why not?A brand name can provide a useful signal of quality for several reasons. First, wheninformation asymmetry is a problem, one solution is to create a “brand-name” product.Standardization of the product produces a reputation for a given level of quality that issignaled by the brand name. Second, if the development of a brand-name reputation iscostly (i.e., advertising, warranties, etc.), the brand name is a signal of higher quality.Finally, pioneer products, by virtue of their “first-mover” status, enjoy consumer loyaltyif the products are of acceptable quality. The uncertainty surrounding newer productsinhibits defection from the pioneering brand-name product.2. Gary is a recent college graduate. After six months at his new job, he has finally saved enough to buy his first car.a. Gary knows very little about the differences between makes and models of cars.How could he use market signals, reputation, or standardization to make comparisons?Gary’s problem is one of asymmetric information. As a buyer of a first car, he will benegotiating with sellers who know more about cars than he does. His first choice is todecide between a new or used car. If he buys a used car, he must choose between aprofessional used-car dealer and an individual seller. Each of these three types ofsellers (the new-car dealer, the used-car dealer, and the individual seller) uses differentmarket signals to convey quality information about their products.The new-car dealer, working with the manufacturer (and relying on the manufacturer’sreputation) can offer standard and extended warranties that guarantee the car willperform as advertised. Because few used cars carry a manufacturer’s warranty and theused-car dealer is not intimately familiar with the condition of the cars on his or her lot(because of their wide variety and disparate previous usage), it is not in his or her self-interest to offer extensive warranties. The used-car dealer, therefore, must rely onreputation, particularly on a reputation of offering “good values.” Since the individualseller neither offers warranties nor relies on reputation, purchasing from such a sellercould make it advisable to seek additional information from an independent mechanicor from reading the used-car recommendations in Consumer Reports. Given his lack ofexperience, Gary should gather as much information about these market signals,reputation, and standardization as he can afford.b. You are a loan officer in a bank. After selecting a car, Gary comes to you seeking aloan. Since he has only recently graduated, he does not have a long credit history.Despite this, the bank has a long history of financing cars of recent college graduates. Is this information useful in Gary’s case? If so, how?The bank’s problem in loaning money to Gary is also one of asymmetric information.Gary has a much better idea than the bank does about the quality of the car and hisability to pay back the loan. While the bank can learn about the car through thereputation of the manufacturer (if it is a new car) and through inspection (if it is a usedcar), the bank has little information on Gary’s ability to handle credit. Therefore, thebank must infer information about Gary’s credit-worthiness from easily availableinformation, such as his recent graduation from college, how much he might haveborrowed while in school, and the similarity of his educational and credit profile to thatof college graduates currently holding car loans from the bank. If recent graduateshave built a good reputation for paying off their loans, Gary can use this reputation tohis advantage, but poor repayment patterns by this group will lessen his chances ofobtaining a car loan from this bank.3. A major university bans the assignment of D or F grades. It defends its action by claiming that students tend to perform above average when they are free from the pressures of flunking out. The university states that it wants all its students to get As and Bs. If the goal is to raise overall grades to the B level or above, is this a good policy? Discuss with respect to the problem of moral hazard.By eliminating the lowest grades, the innovating university creates a moral hazardproblem similar to that which is found in insurance markets. Since they are protectedfrom receiving a below-average grade, some students will have little incentive to workat above-average levels. The policy only addresses the pressures facing below-averagestudents, i.e., those who flunk out. Average and above-average students do not face thepressure of failing. For these students, the destructive pressure of earning good grades(instead of learning a subject well) remains. Their problems are not addressed by thispolicy. Therefore, the policy creates a moral hazard problem primarily for the below-average students who are its intended beneficiaries.4. Professor Jones has just been hired by the economics department at a major private university. The president of the board of regents has stated that the university is committed to providing top-quality education for its undergraduates. Two months into the semester, Professor Jones fails to show up for his classes. It seems he is devoting all his time to economic research rather than to teaching. Professor Jones argues that his research will bring additional prestige to the department and the university. Should he be allowed to continue exclusively with research? Discuss with reference to the principal-agent problem.In the university context, the board of regents and its president are the principals,while the agents are the members of the faculty hired by the department with theapproval of the president and the board. The dual purpose of most universities isteaching students and producing research; thus, most faculty are hired to perform bothtasks. The problem is that teaching effort can be easily monitored (particularly if Jonesdoes not show up for class), while the benefits of establishing a prestigious researchreputation are uncertain and are realized only over time. While the quantity ofresearch is easy to calculate, determining research quality is more difficult. Theuniversity should not simply take Jones’ word regarding the benefits of his researchand allow him to continue exclusively with his research without altering his paymentscheme. One alternative would be to tell Jones that he does not have to teach if he iswilling to accept a lower salary. On the other hand, the university could offer Jones abonus if, due to his research reputation, he is able to bring a lucrative grant or otherdonations to the university5. Faced with a reputation for producing automobiles with poor repair records, a number of American automobile companies have offered extensive guarantees to car purchasers (i.e., a seven-year warranty on all parts and labor associated with mechanical problems). a. In light of your knowledge of the lemons market, why is this a reasonable policy?In the past, American companies enjoyed a reputation for producing high-quality cars.More recently, faced with competition from Japanese car manufacturers, their productsappeared to customers to be of lower quality. As this reputation spread, customerswere less willing to pay high prices for American cars. To reverse this trend, Americancompanies invested in quality control, improving the repair records of their products.Consumers, however, still considered American cars to be of lower quality (lemons, insome sense), and would not buy them, American companies were forced to signal theimproved quality of their products to their customers. One way of providing thisinformation is through improved warranties that directly address the issue of poorrepair records. This was a reasonable reaction to the “lemons” problem that they faced.b. Is the policy likely to create a moral hazard problem? Explain.Moral hazard occurs when the insured party (here, the owner of an Americanautomobile with an extensive warranty) can influence the probability of the event thattriggers payment (here, the repair of the automobile). The coverage of all parts andlabor associated with mechanical problems reduces the incentive to maintain theautomobile. Hence, a moral hazard problem is created by the offer of extensivewarranties. To avoid this problem, all routine maintenance could be performed as longas the car is under warranty.6. To promote competition and consumer welfare, the Federal Trade Commission requires firms to advertise truthfully. How does truth in advertising promote competition? Why would a market be less competitive if firms advertised deceptively?Truth-in-advertising promotes competition by providing the information necessary forconsumers to make optimal decisions. “Competitive forces” function properly only ifconsumers are aware of all prices (and qualities), so comparisons may be made. In theabsence of truthful advertising, buyers are unable to make these comparisons becausegoods priced identically can be of different quality. Hence, there will be a tendency forbuyers to “stick” with proven products, reducing competition between existing firmsand discouraging entry. Note that monopoly rents may result when consumers stickwith proven products.7. An insurance company is considering issuing three types of fire insurance policies: (i) complete insurance coverage, (ii) complete coverage above and beyond a $10,000 deductible, and (iii) 90 percent coverage of all losses. Which policy is more likely to create moral hazard problems?Moral hazard problems arise with fire insurance when the insured party can influencethe probability of a fire and the magnitude of a loss from a fire. The property owner canengage in behavior that reduces the probability of a fire, for example, by inspecting andreplacing faulty wiring. The magnitude of losses can be reduced by the installation ofwarning systems or the storage of valuables away from areas where fires are likely tostart.After purchasing complete insurance, the insured has little incentive to reduce eitherthe probability or the magnitude of the loss, and the moral hazard problem will besevere. In order to compare a $10,000 deductible and 90 percent coverage, we wouldneed information on the value of the potential loss. Both policies reduce the moralhazard problem of complete coverage. However, if the property is worth less (more)than $100,000, the total loss will be less (more) with 90 percent coverage than with the$10,000 deductible. As the value of the property increases above $100,000, the owner ismore likely to engage in fire prevention efforts under the policy that offers 90 percentcoverage than under the one that offers the $10,000 deductible.8. You have seen how asymmetric information can reduce the average quality of the products sold in a market as low-quality products drive out the high-quality ones. For those markets where asymmetric information is prevalent, would you agree or disagree with each of the following? Explain briefly:a. The government should subsidize Consumer Reports.Asymmetric information implies an unequal access to information by either buyers orsellers, a problem that leads to inefficient markets or market collapse.Although Consumer Reports provides evaluations for products ranging fromhamburgers to washing machines, it refuses to let its name be used as an endorsementof a product. While government support of Consumer Reports would be likely toincrease the ability of consumers to distinguish between high- and low-quality goods, itis probable that the Consumers Union, publisher of Consumer Reports,would rejectgovernment subsidization because such subsidization might taint the objectivity of theorganization. Note that the government has already provided an indirect subsidy to thepublication by granting the Consumers Union nonprofit status.b. The government should impose quality standards — e.g., firms should not be allowedto sell low-quality items.Option b involves a cost of monitoring. After imposing quality standards, thegovernment must either administratively monitor the quality of goods or adjudicatedisputes between the public and the manufacturers. Note, however, that low-qualitygoods may be preferred if they are sufficiently cheaper.c. The producer of a high-quality good will probably want to offer an extensivewarranty.This option provides the least-cost solution to the problems of asymmetric information.It allows the producer to distinguish products from low-quality goods because it is morecostly for the low-quality producer to offer an extensive warranty than for the high-quality producer to offer one.d. The government should require all firms to offer extensive warranties.By requiring all firms to offer extensive warranties, the government negates themarket signaling value of warranties offered by the producers of high-quality goods.9. Two used car dealerships compete side by side on a main road. The first, Harry’s Cars, sells high-quality cars that it carefully inspects and, if necessary, services. It costs Harry, on average, $8,000 to buy and service each car that it sells. The second dealership, Lew’s Motors, sells lower-quality cars. It costs Lew on average only $5,000 for each car that it sells. If consumers knew the quality of the used cars they were buying, they would gladly pay $10,000 on average for cars Harry sells, but only $7,000 on average for the cars Lew sells.Unfortunately, the dealerships are new and have not had time to establish reputations, so consumers don’t know the quality of each dealership’s cars. Consumers shopping at these dealerships figure that they have a 50-50 chance of ending up with a high-quality car, no matter which dealership they go to, and hence are willing to pay $8,500 on average for a car.Harry’s has an idea—it will offer a bumper-to-bumper warranty for all the cars it sells. He knows that a warranty lasting Y years will cost $500Y on average, and it also knows that if Lew’s tries to offer the same warranty, it will cost Lew’s $1000Y on average.(a) Suppose Harry’s offers a one-year warranty on all the cars it sells. Will this generatea credible signal of quality? Will Lew’s match the offer, or will it fail to match it sothat consumers can correctly assume that because of the warranty, Harry’s cars are high quality and hence worth $10,000 on average?If Harry were to offer a one-year warranty, the average cost to him of each car will risefrom $8,000 to $8,500. By offering the warranty, Harry will communicate the highquality of his cars and will be able to sell them for $10,000, which means that Harry’sprofit per car will increase from $500 to $1,500.Lew will not match Harry’s warranty. Without offering the warranty, Lew is able tomake $2,000 per car. If he were to offer the warranty, each car will now cost Lew$7,000, but as consumers will not be able to determine the quality of the cars Lew willmake $1,500 per car.(b) What if Harry offers a two-year warranty on his cars? Will this generate a crediblesignal of quality? What about a three-year warranty?If Harry offers a two-year warranty each car will cost him $9,000. He will earn $1,000per car as consumers will recognize the higher quality of his cars.With a three-year warranty Harry would be making $500 per car, the same that hewould have made had he not signaled the higher quality of his cars with a warranty.Therefore, Harry would not offer a three-year warranty.(c) If you were advising Harry, how long a warranty would you urge him to offer?Explain why.Harry will need to offer a warranty of sufficient length such that Lew will not find itprofitable to match the warranty. Let t denote the number of years of the warranty,then Lew will offer a warranty according to the following inequality:(8,500 - 5,000 - 2,000t) ≤ 7,000 - 5000, or 3/4 ≤t.Therefore, I would advise Harry to offer a nine-month warranty on his cars as Lew willnot find it profitable to match the warranty.。
平狄克《微观经济学》课后答案 2
CHAPTER 2THE BASICS OF SUPPLY AND DEMANDThis chapter departs from the standard treatment of supply and demand basics found in most other intermediate microeconomics textbooks by discussing some of the world’s most important markets (wheat, gasoline, and automobiles) and teaching students how to analyze these markets with the tools of supply and demand.Although most of the discussion of economic theory in this chapter serves as a review, the real-world applications of this theory will be enlightening for students, particularly the material covered in Section 2.5 and Examples 2.5 and 2.6.Some problems plague the understanding of supply and demand analysis. One of the most common sources of confusion is between movements along the demand curve and shifts in demand. Through a discussion of the ceteris paribus assumption, stress that when representing a demand function (either with a graph or an equation), all other variables are held constant. Movements along the demand curve occur only with changes in price. As the omitted factors change, the entire demand function shifts. Students may also find a review of how to solve two equations with two unknowns helpful.To stress the quantitative aspects of the demand curve to students, make the distinction between quantity demanded as a function of price, Q = D(P), and the inverse demand function, where price is a function of the quantity demanded, P = D-1(Q). This may clarify the positioning of price on the Y-axis and quantity on the X-axis.Students may also question how the market adjusts to a new equilibrium. One simple mechanism is the partial-adjustment cobweb model. A discussion of the cobweb model (based on traditional corn-hog cycle or any other example) adds a certain realism to the discussion and is much appreciated by students.Although this chapter introduces demand, income, and cross-price elasticities, you may find it more appropriate to return to income and cross-price elasticity after demand elasticity is reintroduced in Chapter 4. If you wait, you should postpone Exercise (7) until income and cross-price elasticities are discussed.1. Suppose that unusually hot weather causes the demand curve for ice cream to shift to the right. Why will the price of ice cream rise to a new market-clearing level?Assume the supply curve is fixed. The unusually hot weather will cause a rightwardshift in the demand curve, creating short-run excess demand at the current price.Consumers will begin to bid against each other for the ice cream, putting upwardpressure on the price. The price of ice cream will rise until the quantity demanded andthe quantity supplied are equal.4. Why do long-run elasticities of demand differ from short-run elasticities? Consider two goods: paper towels and televisions. Which is a durable good? Would you expect the price elasticity of demand for paper towels to be larger in the short-run or in the long-run? Why? What about the price elasticity of demand for televisions?Long-run and short-run elasticities differ based on how rapidly consumers respond toprice changes and how many substitutes are available. If the price of paper towels, anon-durable good, were to increase, consumers might react only minimally in the shortrun. In the long run, however, demand for paper towels would be more elastic as newsubstitutes entered the market (such as sponges or kitchen towels). In contrast, thequantity demanded of durable goods, such as televisions, might change dramatically inthe short run following a price change. For example, the initial influence of a priceincrease for televisions would cause consumers to delay purchases because durablegoods are built to last longer. Eventually consumers must replace their televisions asthey wear out or become obsolete; therefore, we expect the demand for durables to bemore elastic in the long run.5. Explain why, for many goods, the long-run price elasticity of supply is larger than the short-run elasticity.The elasticity of supply is the percentage change in the quantity supplied divided by thepercentage change in price. An increase in price induces an increase in the quantitysupplied by firms. Some firms in some markets may respond quickly and cheaply toprice changes. However, other firms may be constrained by their production capacity inthe short run. The firms with short-run capacity constraints will have a short-runsupply elasticity that is less elastic. However, in the long run all firms can increasetheir scale of production and thus have a larger long-run price elasticity.6. Suppose the government regulates the prices of beef and chicken and sets them below their market-clearing levels. Explain why shortages of these goods will develop and what factors will determine the sizes of the shortages. What will happen to the price of pork? Explain briefly.If the price of a commodity is set below its market-clearing level, the quantity that firmsare willing to supply is less than the quantity that consumers wish to purchase. Theextent of the excess demand implied by this response will depend on the relativeelasticities of demand and supply. For instance, if both supply and demand are elastic,the shortage is larger than if both are inelastic. Factors such as the willingness ofconsumers to eat less meat and the ability of farmers to change the size of their herdsand produce less determine these elasticities and influence the size of excess demand.Rationing will result in situations of excess demand when some consumers are unableto purchase the quantities desired. Customers whose demands are not met willattempt to purchase substitutes, thus increasing the demand for substitutes and raisingtheir prices. If the prices of beef and chicken are set below market-clearing levels, theprice of pork will rise.7. In a discussion of tuition rates, a university official argues that the demand for admission is completely price inelastic. As evidence she notes that while the university has doubled its tuition (in real terms) over the past 15 years, neither the number nor quality of students applying has decreased. Would you accept this argument? Explain briefly. (Hint: The official makes an assertion about the demand for admission, but does she actually observe a demand curve? What else could be going on?)If demand is fixed, the individual firm (a university) may determine the shape of thedemand curve it faces by raising the price and observing the change in quantity sold.The university official is not observing the entire demand curve, but rather only theequilibrium price and quantity over the last 15 years. If demand is shifting upward, assupply shifts upward, demand could have any elasticity. (See Figure 2.7, for example.)Demand could be shifting upward because the value of a college education hasincreased and students are willing to pay a high price for each opening. More marketc. A drought shrinks the apple crop to one-third its normal size.The supply curve would shift in, causing the equilibrium price to rise and theequilibrium quantity to fall.d. Thousands of college students abandon the academic life to become apple pickers.The increased supply of apple pickers will lead to a decrease in the cost of bringingapples to market. The decreased cost of bringing apples to market results in anoutward shift of the supply curve of apples and causes the equilibrium price to fall andthe equilibrium quantity to increase.e. Thousands of college students abandon the academic life to become apple growers.This would result in an outward shift of the supply curve for apples, causing theequilibrium price to fall and the equilibrium quantity to increase.1. Consider a competitive market for which the quantities demanded and supplied (per year) at various prices are given as follows:Price($)Demand (millions) Supply (millions) 6022 14 8020 16 10018 18 12016 20 a. Calculate the price elasticity of demand when the price is $80. When the price is$100.We know that the price elasticity of demand may be calculated using equation 2.1 fromthe text:E Q Q P PP Q Q PD D D D D ==∆∆∆∆. With each price increase of $20, the quantity demanded decreases by 2. Therefore,∆∆Q P DF HG I K J =-=-22001.. At P = 80, quantity demanded equals 20 andE D =F HG I KJ -=-802001040...b g Similarly, at P = 100, quantity demanded equals 18 andE D =F HG I K J -=-1001801056...b g b. Calculate the price elasticity of supply when the price is $80. When the price is $100.The elasticity of supply is given by:E Q Q P P Q Q PS S S S S ==∆∆∆∆. With each price increase of $20, quantity supplied increases by 2. Therefore,∆∆Q SF HG I K J ==22001.. At P = 80, quantity supplied equals 16 andE S =F HG I KJ =80160105..bg .Similarly, at P = 100, quantity supplied equals 18 andE S=FH GIK J= 1001801056...bgc. What are the equilibrium price and quantity?The equilibrium price and quantity are found where the quantity supplied equals thequantity demanded at the same price. As we see from the table, the equilibrium priceis $100 and the equilibrium quantity is 18 million.d. Suppose the government sets a price ceiling of $80. Will there be a shortage, and, ifso, how large will it be?With a price ceiling of $80, consumers would like to buy 20 million, but producers willsupply only 16 million. This will result in a shortage of 4 million.2. Refer to Example 2.3 on the market for wheat. Suppose that in 1985 the Soviet Union hadbought an additional 200 million bushels of U.S. wheat. What would the free market price of wheat have been and what quantity would have been produced and sold by U.S. farmers?The following equations describe the market for wheat in 1985:QS= 1,800 + 240PandQD= 2,580 - 194P.If the Soviet Union had purchased an additional 200 million bushels of wheat, the newdemand curve 'Q D, would be equal to Q ED + 200, or'Q D= (2,580 - 194P) + 200 = 2,780 - 194PEquating supply and the new demand, we may determine the new equilibrium price,1,800 + 240P = 2,780 - 194P, or434P = 980, or P* = $2.26 per bushel.To find the equilibrium quantity, substitute the price into either the supply or demandequation, e.g.,QS= 1,800 + (240)(2.26) = 2,342andQD= 2,780 - (194)(2.26) = 2,342.3. The rent control agency of New York City has found that aggregate demand is QD= 100 - 5P measured in tens of thousands of apartments, and price, the average monthly rental rate, P, with quantity measured in hundreds of dollars. The agency also noted that the increase in Q at lower P results from more three-person families coming into the city from Long Island and demanding apartments. The city’s board of realtors acknowledges that this is agood demand estimate and has shown that supply is QS= 50 + 5P.a. If both the agency and the board are right about demand and supply, what is the freemarket price? What is the change in city population if the agency sets a maximum average monthly rental of $100, and all those who cannot find an apartment leave the city?To find the free market price for apartments, set supply equal to demand:100 - 5P = 50 + 5P, or P = $500.Substituting the equilibrium price into either the demand or supply equation todetermine the equilibrium quantity:QD= 100 - (5)(5) = 75andQ S = 50 + (5)(5) = 75.We find that at the rental rate of $500, 750,000 apartments are rented.If the rent control agency sets the rental rate at $100, the quantity supplied would thenbe 550,000 (Q S = 50 + (5)(100) = 550), a decrease of 200,000 apartments from the freemarket equilibrium. (Assuming three people per family per apartment, this wouldimply a loss of 600,000 people.) At the $100 rental rate, the demand for apartments is950,000 units, and the resultant shortage is 400,000 units.b. Suppose the agency bows to the wishes of the board and sets a rental of $900 permonth on all apartments to allow landlords a “fair” rate of return. If 50 percent of any long-run increases in apartment offerings comes from new construction, how many apartments are constructed?At a rental rate of $900, the supply of apartments would be 50 + 5(9) = 95, or 950,000units, which is an increase of 200,000 units over the free market equilibrium.Therefore, (0.5)(200,000) = 100,000 units would be constructed. Note, however, thatsince demand is only 550,000 units, 400,000 units would go unrented.4. Much of the demand for U.S. agricultural output has come from other countries. From Example 2.3, total demand is Q = 3,550 - 266P . In addition, we are told that domestic demand is Q d = 1,000 - 46P . Domestic supply is Q S = 1,800 + 240P . Suppose the export demand for wheat falls by 40 percent.a. U.S. farmers are concerned about this drop in export demand. What happens to thefree market price of wheat in the United States? Do the farmers have much reason to worry?Given total demand, Q = 3,550 - 266P , and domestic demand, Q d = 1,000 - 46P , we maysubtract and determine export demand, Q e = 2,550 - 220P .The initial market equilibrium price is found by setting total demand equal to supply:3,550 - 266P - 1,800 + 240P , orP = $3.46.There are two different ways to handle the 40 percent drop in demand. One way is toassume that the demand curve shifts down so that at all prices demand decreases by 40percent. The second way is to rotate the demand curve in a clockwise manner aroundthe vertical intercept (i.e. in the current case the demand curve would becomeQ = 3,550 - 159.6P ). We apply the former approach in the solution to exercises here.Regardless of the two approaches, the effect on prices and quantity will be qualitativelythe same, but will differ quantitatively.Therefore, if export demand decreases by 40 percent, total demand becomesQ D = Q d + 0.6Q e = 1,000 - 46P + (0.6)(2,550 - 220P ) = 2,530 - 178P .Equating total supply and total demand,1,800 + 240P = 2,530 - 178P , orP = $1.75,which is a significant drop from the market-clearing price of $3.46 per bushel. At thisprice, the market-clearing quantity is 2,219 million bushels. Total revenue hasdecreased from $9.1 billion to $3.9 billion. Most farmers would worry.b. Now suppose the U.S. government wants to buy enough wheat each year to raise theprice to $3.00 per bushel. Without export demand, how much wheat would the government have to buy each year? How much would this cost the government?With a price of $3, the market is not in equilibrium. Demand = 1000 - 46(3) = 862.Supply = 1800 + 240(3) = 2,520, and excess supply is therefore 2,520 - 862 = 1,658. Thegovernment must purchase this amount to support a price of $3, and will spend $3(1.66million) = $5.0 billion per year.5. In Example 2.6 we examined the effect of a 20 percent decline in copper demand on the price of copper, using the linear supply and demand curves developed in Section 2.5. Suppose the long-run price elasticity of copper demand were -0.4 instead of -0.8.a. Assuming, as before, that the equilibrium price and quantity are P* = 75 cents perpound and Q* = 7.5 million metric tons per year, derive the linear demand curve consistent with the smaller elasticity.Following the method outlined in Section 2.5, we solve for a and b in the demandequation Q D = a - bP . First, we know that for a linear demand function E b P D =-F H G I KJ *. Here E D = -0.4 (the long-run price elasticity), P* = 0.75 (the equilibrium price), and Q* =7.5 (the equilibrium quantity). Solving for b , -=-F H I K0407575...b , or b = 4. To find the intercept, we substitute for b , Q D (= Q *), and P (= P *) in the demandequation:7.5 = a - (4)(0.75), or a = 10.5.The linear demand equation consistent with a long-run price elasticity of -0.4 isthereforeQ D = 10.5 - 4P .b. Using this demand curve, recalculate the effect of a 20 percent decline in copperdemand on the price of copper.The new demand is 20 percent below the original (using our convention that the wholedemand curve is shifted down by 20 percent):'Q D =-=-0810548432....a f a fP P . Equating this to supply,8.4 - 3.2P = -4.5 + 16P , orP = 0.672.With the 20 percent decline in the demand, the price of copper falls to 67.2 cents perpound.6. Example 2.7 analyzes the world oil market. Using the data given in that example,a. Show that the short-run demand and competitive supply curves are indeed given byD = 24.08 - 0.06PS C = 11.74 + 0.07P .First, considering non-OPEC supply:S c = Q * = 13.With E S = 0.10 and P * = $18, E S = d (P */Q *) implies d = 0.07.Substituting for d , S c , and P in the supply equation, c = 11.74 and S c = 11.74 + 0.07P .Similarly, since Q D = 23, E D = -b (P */Q *) = -0.05, and b = 0.06. Substituting for b , Q D = 23, and P = 18 in the demand equation gives 23 = a - 0.06(18), so that a = 24.08.Hence Q D = 24.08 - 0.06P .b. Show that the long-run demand and competitive supply curves are indeed given byD = 32.18 - 0.51PS C = 7.78 + 0.29P .As above, E S = 0.4 and E D = -0.4: E S = d (P */Q *) and E D = -b(P*/Q*), implying 0.4 = d (18/13)and -0.4 = -b (18/23). So d = 0.29 and b = 0.51.Next solve for c and a :S c = c + dP and Q D = a - bP , implying 13 = c + (0.29)(18) and 23 = a - (0.51)(18).So c = 7.78 and a = 32.18.c. Use this model to calculate what would happen to the price of oil in the short-runand the long-run if OPEC were to cut its production by 6 billion barrels per year.With OPEC’s supply reduced from 10 bb/yr to 4 bb/yr, add this lower supply of 4 bb/yr to the short-run and long-run supply equations:S c ' = 4 + S c = 11.74 + 4 + 0.07P = 15.74 + 0.07P and S " = 4 + S c = 11.78 + 0.29P .These are equated with short-run and long-run demand, so that:15.74 + 0.07P = 24.08 - 0.06P ,implying that P = $64.15 in the short run; and11.78 + 0.29P = 32.18 - 0.51P ,implying that P = $24.29 in the long run.7.Refer to Example 2.8, which analyzes the effects of price controls on natural gas. a. Using the data in the example, show that the following supply and demand curvesdid indeed describe the market in 1975:Supply: Q = 14 + 2P G + 0.25P ODemand: Q = -5P G + 3.75P Owhere P G and P O are the prices of natural gas and oil, respectively. Also, verify that if the price of oil is $8.00, these curves imply a free market price of $2.00 for natural gas.To solve this problem, we apply the analysis of Section 2.5 to the definition of cross-price elasticity of demand given in Section 2.3. For example, the cross-price-elasticity of demand for natural gas with respect to the price of oil is:E Q P P Q GO G O G G=F HG I K J FH GI KJ ∆∆. ∆∆Q P G O F H G IK J is the change in the quantity of natural gas demanded, because of a small change in the price of oil. For linear demand equations,∆∆Q P G O F H G I K J is constant. If we represent demand as:Q G = a - bP G + eP O(notice that income is held constant), then∆∆Q P G OF HG I K J = e . Substituting this into the cross-price elasticity, E e P Q PO O G=F H G I K J **, where P O * and Q G * are the equilibrium price and quantity. We know that P O * = $8 and Q G* = 20 trillion cubic feet (Tcf). Solving for e , 15820.=F H G I KJ e , or e = 3.75. Similarly, if the general form of the supply equation is represented as:Q G = c + dP G + gP O , the cross-price elasticity of supply is g P Q OG**F H G I K J , which we know to be 0.1. Solving for g , ⎪⎭⎫ ⎝⎛=2081.0g , or g = 0.25. The values for d and b may be found with equations 2.5a and 2.5b in Section 2.5. Weknow that E S = 0.2, P* = 2, and Q* = 20. Therefore,⎪⎭⎫ ⎝⎛=2022.0d , or d = 2.Also, E D = -0.5, so⎪⎭⎫ ⎝⎛=-2025.0b , or b = -5. By substituting these values for d, g, b , and e into our linear supply and demandequations, we may solve for c and a :20 = c + (2)(2) + (0.25)(8), or c = 14,and20 = a - (5)(2) + (3.75)(8), or a = 0.If the price of oil is $8.00, these curves imply a free market price of $2.00 for naturalgas. Substitute the price of oil in the supply and demand curves to verify theseequations. Then set the curves equal to each other and solve for the price of gas.14 + 2P G + (0.25)(8) = -5P G + (3.75)(8), 7P G = 14, orP G = $2.00.b. Suppose the regulated price of gas in 1975 had been $1.50 per million cubic feet,instead of $1.00. How much excess demand would there have been?With a regulated price of $1.50 for natural gas and a price of oil equal to $8.00 perbarrel,Demand: Q D = (-5)(1.50) + (3.75)(8) = 22.5, andSupply: Q S = 14 + (2)(1.5) + (0.25)(8) = 19.With a supply of 19 Tcf and a demand of 22.5 Tcf, there would be an excess demand of3.5 Tcf.c. Suppose that the market for natural gas had not been regulated. If the price of oilhad increased from $8 to $16, what would have happened to the free market price of natural gas?If the price of natural gas had not been regulated and the price of oil had increasedfrom $8 to $16, thenDemand: Q D = -5P G + (3.75)(16) = 60 - 5P G , andSupply: Q S = 14 + 2P G + (0.25)(16) = 18 + 2P G .Equating supply and demand and solving for the equilibrium price,18 + 2P G = 60 - 5P G , or P G = $6.The price of natural gas would have tripled from $2 to $6.。
平狄克 中级微观经济学第一章课后练习答案_Ch01
Oklahoma and New Jersey represent separate geographic markets for gasoline because of high transportation costs.There would be an opportunity for arbitrage if transportation costs were less
In general, the first class is a good time to pique student interest in the course.It is also a good time to tell students that they need to work hard to learn how to do economic analysis, and that memorization alone will not get them through the course.Students must learn to think like economists, so encourage them to work lots of problems.Also encourage them to draw graphs neatly and large enough to make them easy to interpret.It always amazes me to see the tiny, poorly drawn graphs some students produce.It is no wonder their answers are often incorrect.You might even suggest they bring a small ruler and colored pencils to class as they can draw good diagrams.
最新平狄克微观经济学答案第17-18章
平狄克微观经济学答案第17－18章第十七章复习题1、当买方和卖方之间对商品存在着不对称信息时，即当不同质量的产品的购买者或出售者买卖时没有充分的信息来确定产品的质量，从而不同质量的产品以单一价格出售，逆淘汰问题就出现了，结果市场就有太多的低质量产品和太少的高质量产品出售，低质量产品把高质量的产品逐出了市场，导致市场失灵。
2、多。
3、保险市场的逆淘汰：由于信息的不对称，即使保险公司做身体检查，购买保险的人对他们总的健康情况也比任何保险公司所希望知道不健康的人在被保险人总数中的比例提高了。
这迫使价格上升，从而使那些较健康的人，由于知道自己的低风险，作出不投保决定，这进一步提高了不健康的人的比例，这又迫使保险价格上升，如此等等，直到几乎所有买保险的人都是不健康的人。
保险市场的道德风险：当被保险一方充分保险，而一家信息有限的保险公司又不能准确的监督他的话，被保险方可能采取会提高事故或受伤可能性的行动，当被保险方能影响导致赔偿的事件的可能性或程度时，道德风险就会发生。
4、保证和保证书、产品标准化、保证和保证书5、当不同质量的产品在购买者或出售者买卖时没有充分的住处来确定产品的真实质量，从而不同质量的产品以单一价格出售时，逆淘汰问题就出现了。
存在的根本原因是信息不对称，即买主对产品质量的住处知道的比卖主少的多，如果卖主能发出有关产品的信息，就会消除信息不对称，避免逆淘汰问题的发生，对高质量的产品而言当然是有利的。
保证和保证书有效地发出了产品质量信号，因为一项内容广泛的保证书对低质量的产品的生产者来说要比高质量产品的生产者成本更高（在保证书下，低质量产品更需要修理服务，而这都将由生产者支付）。
结果，出于他们的利益，低质量产品的生产者就不会提供内容广泛的保证书。
消费者就能因此而把一项社会主义少保证书看作是高质量的信号屏为提供保证书的商品支付较多的钱。
6、因为大多数企业业主并不能监督总经理所作的一切，总经理的住处比业主多的多，这种信息的不对称，产生委托——代理问题，即，经理可以追求他们的自己的目标，甚至不惜以获得较低利润为代价。
平狄克微观经济学答案第10-11章-17页文档资料
第十章复习题1．该垄断者减少产量，直到边际成本等于边际收益。
2．P MC P E D-=-1 该等式表明，当弹性上升（需求变得更加有弹性），弹性相反数的下降和度量市场力的下降，因而当弹性上升（下降），厂商有更少（多）能力使价格高于边际成本。
3．垄断者的产出决定由需求曲线和边际成本决定。
因而需求的变动不仅像竞争的供给曲线那样给出一系列价格和产量，而且需求的变动可以导致价格改变但产量并不变，也可以导致产量改变而价格不变。
他们不存在价格和产量之间的一一对应关系，因自垄断市场没有供给曲线。
4．垄断力量的程度或一个厂商左右市场的力量取决于面对的需求曲线的弹性。
因此如果厂商的需求曲线的弹性小于无穷，厂商就有一些垄断势力。
5．来源于3个方面：（1）市场需求弹性，如，欧佩克利用石油在短期是无弹性而控制油价（2）厂商的数目，如，某3个厂商控制某一产品的市场份额，他们就有了垄断势力（3）厂商间的相互作用，如，几个主要的厂商相互串通，那么他们就能产生垄断势力。
6．同上7．垄断势力的结果是较高的价格和较低的产量，容易使消费者的利益受损,消费者剩余就会减少。
同时厂商可能用一些非生产的方式来保持他的垄断地位，从而使社会成本更大。
8． 藉由在垄断者的取利润最大值的价格下面限制价格，政府能改变厂商的边际收益曲线的形状。
当价格极高被征税的时候，边际收益为比以极高价格量低的量和极高价格相等。
如果政府取输出最大值,它应该将一个价格对手设定为边际成本。
价格在这一个水平下面引诱公司减少制造, 假定边际成本曲线正在以上难以下咽的食物。
调整者的问题要决定垄断的边际成本曲线的形状。
9. 边际的支出是在总支出方面的改变如被购买的量的变化。
对于为购买由于许多厂商竞争的一个厂商，边际的支出和平均支出相等。
所有的厂商应该购买以便最后一个单位的边际价值和在那一个单位上的边际支出相等。
这对两者的竞争买主和垄断者是真实的。
10. 买方垄断势力是购买者影响一种货物价格的能力。
平狄克微观经济学答案——第10章卖方垄断与买方垄断
P MC 1
P
Ed
或者
P MC
1
1 Ed
在题目中， Ed 2.0 ，所以1/ Ed 1/ 2 ，价格可以定为：
P MC 2MC 1 2
因此，当 MC 升高 25％，价格也应当升高 25％。当 MC＝$20,.P=$40。当 MC 升高到 $20*(1.25)＝$25 时，价格应当升到$50，升高 25％。 4．一厂商面临如下的平均收益（需求）曲线：
2所以2me曲线于边际价值曲线交于2?depmcp1?????d?????????????dmcp11?在题目中?e211??de价格可以定为
第三部分 企业结构 第十章 市场势力：卖方垄断与买方垄断
教学注解 这一章同时涵盖了卖方垄断与买方垄断两部分，旨在揭示两种类型市场势 力的相似性。本章开始的 1－4 节讨论的是卖方垄断。第 5 节首先讨论买方垄断， 然后提出卖方垄断与买方垄断的指导性比较。第 6 节讨论买方势力的来源及其 社会成本。第 7 节以对反垄断法的讨论终结本章。如果时间较紧，你可以只讲 述有关卖方垄断的前 4 节而略去本章其余部分。你可以讲述第 7 节即便略去了 5、6 节。第 1 节最后有关复合企业的部分同样可以略去。 尽管第 8 章讲述了利润最大化的一般规则，你应当通过对方程 10.1 的推导 复习边际收入及供给的价格弹性。对方程 10.1 推导的讨论有助于说明图形 10.3 的几何意义。指出对于买方垄断者而言，由于利润最大化处的价格及产量所对 应的边际收入为正，该产量处的弹性较大。同时，方程 10.1 直接引出了 10.2 节 的勒纳指数。这为卖方垄断市场势力的讨论奠定了坚实的基础。比如说，如果 Ed 较大（如由于高度替代品），那么，（1）需求曲线相对平坦，（2）边际收入 曲线相对平坦（尽管比需求曲线陡峭），（3）卖方垄断者难以使价格超出边际成 本很多。为了强调这一点，可以引入非线性需求曲线，比如，展示单位弹性需 求曲线的边际收入曲线的位置。一旦这些概念讲清楚了，对于面对非线性需求 曲线的卖方垄断厂商征税效果的讨论就不是那么困难了。 市场势力的社会成本是课堂讨论的较好话题。对于卖方垄断造成的无谓损 失可以与第 9 章的市场干预分析加以比较引出。比如将图 10.10 与图 9.5 进行比 较。考虑到练习（9），（13），（15）涉及了“拐折的边际收入曲线”，如果你要 布置这些作业，你应当讲解图 10.11。尽管图 10.11 很复杂，在这里涉及有助于 12 章重现时的理解。
平狄克微观经济学答案——第17章信息不对称的市场
第17章信息不对称的市场教学注解这一章探求了一部分人比另一部分人知道得更多时的不同情况，或者换言之，当存在不对称信息时会发生什么。
17.1节讨论了卖方比买方拥有更多信息的情况，17.2节讨论了市场信号机制处理不对称信息的问题。
17.3节讨论了当一方对自己的行为比另一方了解得更多时的道德风险。
17.4节讨论了委托——代理问题，17.5节扩展了一体化企业案例的分析。
两节都讲述了所有者与经理的目标不一致的问题。
17.6节检验了效率工资问题。
基本上有四个话题可由指导教师根据时间限制和大多数兴趣从中挑选。
介绍不对称信息最好通过复习微观经济学以完全信息为假定来展开。
例如，除了第5章和15章的几节，我们以对未来完全已知为假设（无不确定性）。
在不确定模型中，消费者和生产者与自然规律博弈。
在不对称信息模型中，他们互相博弈。
你的许多学生可能买卖或将要买卖旧车，因此，他们会觉得柠檬模型有趣。
通过询问旧车的卖者他们如何定价来开始你的讲解。
在展示图17.1前强调对于模型的直觉。
如果他们弄懂了这一模型，他们应当索要更高的价格，以变给买者留下他们的车质量高的印象。
课堂讨论可以考虑政府是否应通过立法，要求出售旧车时提供保证书。
保险市场也是大多数学生所熟悉的市场。
尽管许多州要求汽车保险，责任限制可能每个保险单都不同。
(liability limits may vary from policy to policy.)讨论风险规避者怎样想购买更高赔偿额度的保险单，以及保险公司怎样决定保险的风险。
如果你在15章用了购买房屋的案例，这里你可以通过考虑银行家怎样决定借款者是否违约将其扩展。
当讨论市场信号时，支出教育的双重作用（作为培训和更高生产率的信号）。
在17.2节展示的“工作市场信号的简单模型”，可能会使不熟悉不连续函数的学生困惑不解（见图17.2）。
解释教育程度怎样导致不连续性，强调教育质量的程度、保证和担保的关系。
（stress the relationship between degrees,guarantees,and warranties of educational quality.）道德风险是一个用例子容易解释的概念，但对逆向选择和道德风险的清晰的区别是重要的。
平狄克《微观经济学》课后答案 10
CHAPTER 10MARKET POWER: MONOPOLY AND MONOPSONYIn most textbooks, the title of this chapter would be “Monopoly,” and monopsony would be found in a section of the chapter on factor markets. This text, however, gives monopoly and monopsony parallel treatment. There is an initial discussion of monopoly (Sections 1-4), a briefer discussion of monopsony (Section 5), and a joint consideration of the two (Section 6). Exercises (1) through (5) focus on the monopolist’s determination of a profit-maximizing output. Exercises (6) and (7) explore the multiplant firm. Exercise (8) examines the decision in the U.S. antitrust case against Alcoa. Exercises (10) and (12) examine monopsony power. Exercises (9), (13),(14), and (15) focus on price regulation.Although previous chapters have presented the rule for profit maximization, you should briefly review marginal revenue and price elasticity of demand through a careful derivation of Equation 10.1. A discussion of the derivation of Equation 10.1 will elucidate the geometry of Figure 10.3: illustrate that because the monopolist chooses a quantity such that marginal revenue is positive, demand at that quantity is elastic. Equation 10.1 also leads directly to the Lerner Index in Section 10.2. This pro vides fruitful ground for a discussion of a monopolist’s market power. For example, if E d is large (e.g., because of close substitutes), then (1) the demand curve is flat, (2) the marginal revenue curve is flat (although steeper than the demand curve), and (3) the monopolist has little power to raise price above marginal cost. To reinforce these points, introduce a non-linear demand curve by, for example, showing the location of the marginal revenue curve for a unit-elastic demand curve. Once this concept has been clearly presented, the discussion of the effect of an excise tax on a monopolist with non-linear demand (Figure 10.5) will not seem out of place.The social response to market power provides a good topic for class discussion, and this topic can be introduced by comparing the deadweight loss with the analysis of market intervention given in Chapter 9. For example, compare Figure 10.9 with Figure 9.6. Because Exercises (9), (13), and (15) involve “kinked marginal revenue curves,” you should pres ent Figure 10.10 if you plan to assign those problems. Although Figure 10.10 is complicated, exposure to it here will help when it reappears in Chapter 12.1. When marginal cost is greater than marginal revenue, the incremental cost of the last unit produced is greater than incremental revenue. The firm would increase its profit by not producing the last unit. It should continue to reduce production, thereby decreasing marginal cost and increasing marginal revenue, until marginal cost is equal to marginal revenue.2. We can show that this measure of market power is equal to the negative inverse of the price elasticity of demand.P MC P E D-=-1 The equation implies that, as the elasticity increases (demand becomes more elastic), the inverse of elasticity decreases and the measure of market power decreases. Therefore, as elasticity increases (decreases), the firm has less (more) power to increase price above marginal cost.3. The monopolist’s output decision depends not only on mar ginal cost, but also on the demand curve. Shifts in demand do not trace out a series of prices and quantities that we can identify as the supply curve for the firm. Instead, shifts in demand lead to changes in price, output, or both. Thus, there is no one-to-one correspondence between the price and the seller’s quantity; therefore, a monopolized market lacks a supply curve.4. The degree of monopoly power or market power enjoyed by a firm depends on the elasticity of the demand curve that it faces. As the elasticity of demand increases, i.e., as the demand curve becomes flatter, the inverse of the elasticity approaches zero and the monopoly power of the firm decreases. Thus, if the firm’s demand curve has any elasticity less than infinity, the firm has some monopoly power.5. The firm’s exploitation of its monopoly power depends on how easy it is for other firms to enter the industry. There are several barriers to entry, including exclusive rights (e.g., patents, copyrights, and licenses) and economies of scale. These two barriers to entry are the most common. Exclusive rights are legally granted property rights to produce or distribute a good or service. Positive economies of scale lead to “natural monopolies” because the largest producer can charge a lower price, driving competition from the market. For example, in the production of aluminum, there is evidence to suggest that there are scale economies in the conversion of bauxite to alumina. (See U.S. v. Aluminum Company of America , 148 F.2d 416 [1945], discussed in Exercise 7, below.)6. Three factors determine the firm’s elasticity of demand: (1) the elasticity of market demand, (2) the number of firms in the market, and (3) interaction among the firms in the market. The elasticity of market demand dependson the uniqueness of the product, i.e., how easy it is for consumers to substitute away from the product. As the number of firms in the market increases, the demand elasticity facing each firm increases because customers may shift to the fir m’s competitors. The number of firms in the market is determined by how easy it is to enter the industry (the height of barriers to entry). Finally, the ability to raise the price above marginal cost depends on how other firms react to the firm’s price c hanges. If other firms match price changes, customers will have little incentive to switch to another supplier.7. When the firm exploits its monopoly power to raise the price above marginal cost, consumers buy less at the higher price. Consumers enjoy less surplus, the difference between the price they are willing to pay and the market price on each unit consumed. Some of the lost consumer surplus is not captured by the seller and is a deadweight loss to society. Therefore, if the gains to producers were redistributed to consumers, society would still suffer the deadweight loss.8. By restricting price below the monopolist’s profit-maximizing price, the government can change the shape of the firm’s marginal revenue, MR, curve. When a price ceiling is imposed, MR is equal to the price ceiling for all quantities lower than the quantity demanded at the price ceiling. If the government wants to maximize output, it should set a price equal to marginal cost. Prices below this level induce the firm to decrease production, assuming the marginal cost curve is upward sloping. The regulator’s problem is to determine the shape of the monopolist’s marginal cost curve. This task is difficult given the monopolist’s incentive to hide or distort this information.9. The marginal expenditure is the change in the total expenditure as the purchased quantity changes. For a firm competing with many firms for inputs, the marginal expenditure is equal to the average expenditure (price). For a monopsonist, the marginal expenditure curve lies above the average expenditure curve because the decision to buy an extra unit raises the price that must be paid for all units, including the last unit. All firms should buy inputs so that the marginal value of the last unit is equal to the marginal expenditure on that unit. This is true for both the competitive buyer and the monopsonist. However, because the monopsonist’s marginal expenditure curve lies above the average expenditure curve and because the marginal value curve is downward sloping, the monopsonist buys less than a firm would buy in a competitive market.10. Monopsony power is the power in the factor market held by the buyer. A buyer facing an upward-sloping factor supply curve has some monopsony power. In a competitive market, the seller faces a perfectly-elastic market curve and the buyer faces a perfectly-elastic supply curve. Thus, any characteristic of the market (e.g., when there is a small number of buyers or if buyers engage in collusive behavior) that leads to a less-than-perfectly-elastic supply curve gives the buyer some monopsony power.11. The individual firm’s monopsony power depends on the characteristics of the “buying-side” of the market. There are three characteristics that enhance monopsony power: (1) the elasticity of market supply, (2) the number of buyers, and (3) how the buyers interact. The elasticity of market supply depends on how responsive producers are to changes in price. If, in the short run, supply is relatively fixed, then supply is relatively inelastic. For example, since tobacco farmers can sell their crop to only a handful of tobacco product producers, the power to buy at a price below marginal value is increased.12. With monopsony power, the price is lower and the quantity is less than under competitive buying conditions. Because of the lower price and reduced sales, sellers lose revenue. Only part of this lost revenue is transferred to the buyer as consumer surplus, and the net loss in total surplus is deadweight loss. Even if the consumer surplus could be redistributed to sellers, the deadweight loss persists. This inefficiency will remain because quantity is reduced below a level where price is equal to marginal cost.13. Antitrust laws, which are subject to interpretation by the courts, limit market power by proscribing a firm’s behavior in attempting to maximize profit. Section 1 of the Sherman Act prohibits every restraint of trade, including any attempt to fix prices by buyers or sellers. Section 2 of the Sherman Act prohibits behavior that leads to monopolization. The Clayton Act, with the Robinson-Patman Act, prohibits price discrimination and exclusive dealing (sellers prohibiting buyers from buying goods from other sellers). The Clayton Act also limits mergers when they could substantially lessen competition. The Federal Trade Commission Act makes it illegal to use unfair or deceptive practices.14. Antitrust laws are enforced in three ways: (1) through the Antitrust Division of the Justice Department, whenever firms violate federal statutes, (2) through the Federal Trade Commission, whenever firms violate the Federal Trade Commission Act, and (3) through civil suits. The Justice Department can seek to impose fines or jail terms on managers or owners involved or seek to reorganize the firm, as it did in its case against A.T.& T. The FTC can seek a voluntary understanding to comply with the law or a formal Commission order. Individuals or companies can sue in federal court for awards equal to three times the damage arising from the anti-competitive behavior.1. As illustrated in Figure 10.4b in the textbook, an increase in demand need not always result in a higher price. Under the conditions portrayed in Figure 10.4b, the monopolist supplies different quantities at the same price. Similarly, an increase in supply facing the monopsonist need not always result in a higher price. Suppose theaverage expenditure curve shifts from AE 1 to AE 2, as illustrated in Figure 10.1. With the shift in the average expenditure curve, the marginal expenditure curve shifts from ME 1 to ME 2. The ME 1 curve intersects the marginal value curve (demand curve) at Q 1, resulting in a price of P . When the AE curve shifts, the ME 2 curve intersects the marginal value curve at Q 2 resulting in the same price at P .Figure 10.12. As a large producer of farm equipment, Caterpillar Tractor has market power and should consider the entire demand curve when choosing prices for its products. As their advisor, you should focus on the determination of the elasticity of demand for each product. There are three important factors to be considered. First, how similar are the products offered by Caterpillar’s competitors? If they are close substitutes, a small incr ease in price could induce customers to switch to the competition. Secondly, what is the age of the existing stock of tractors? With an older population of tractors, a 5 percent price increase induces a smaller drop in demand. Finally, because farm tractors are a capital input in agricultural production, what is the expected profitability of the agricultural sector? If farm incomes are expected to fall, an increase in tractor prices induces a greater decline in demand than one would estimate with information on only past sales and prices.3. Yes. The monopolist’s pricing rule as a function of the elasticity of demand for its product is:(P -MC)P = - 1E dor alternatively,d E 1 + 1MC= P ⎪⎪⎪⎭⎫ ⎝⎛⎪⎪⎪⎭⎫ ⎝⎛In this example E d = -2.0, so 1/E d = -1/2; price should then be set so that:2MC = 21MC = P ⎪⎪⎭⎫ ⎝⎛ Therefore, if MC rises by 25 percent price, then price will also rise by 25 percent. When MC = $20, P = $40. When MC rises to $20(1.25) = $25, the price rises to $50, a 25% increase.4. a. The profit-maximizing output is found by setting marginal revenue equal to marginal cost. Given a linear demand curve in inverse form, P = 100 - 0.01Q , we know that the marginal revenue curve will have twice the slope of the demand curve. Thus, the marginal revenue curve for the firm is MR = 100 - 0.02Q . Marginal cost is simply the slope of the total cost curve. The slope of TC = 30,000 + 50Q is 50. So MC equals 50. Setting MR = MC to determine the profit-maximizing quantity:100 - 0.02Q = 50, orQ = 2,500.Substituting the profit-maximizing quantity into the inverse demand function to determine theprice:P = 100 - (0.01)(2,500) = 75 cents.Profit equals total revenue minus total cost:π = (75)(2,500) - (30,000 + (50)(2,500)), orπ = $325 per week.b.Suppose initially that the consumers must pay the tax to the government. Since the total price (including the tax) consumers would be willing to pay remains unchanged, we know that the demand function isP* + T = 100 - 0.01Q, orP* = 100 - 0.01Q - T,where P* is the price received by the suppliers. Because the tax increases the price of each unit, total revenue for the monopolist decreases by TQ, and marginal revenue, the revenue on each additional unit, decreases by T:MR = 100 - 0.02Q - Twhere T = 10 cents. To determine the profit-maximizing level of output with the tax, equate marginal revenue with marginal cost:100 - 0.02Q - 10 = 50, orQ = 2,000 units.Substituting Q into the demand function to determine price:P* = 100 - (0.01)(2,000) - 10 = 70 cents.Profit is total revenue minus total cost:()()()()()000,100000,30000,250000,270=+-=πcents, or$100 per week.Note: The price facing the consumer after the imposition of the tax is 80 cents. The monopolist receives 70 cents. Therefore, the consumer and the monopolist each pay 5 cents of the tax.If the monopolist had to pay the tax instead of the consumer, we would arrive at the same result. The monopolist’s cost function would then beTC = 50Q + 30,000 + TQ = (50 + T)Q + 30,000.The slope of the cost function is (50 + T), so MC = 50 + T. We set this MC to the marginal revenue function from part (a):100 - 0.02Q = 50 +10, orQ = 2,000.Thus, it does not matter who sends the tax payment to the government. The burden of the tax is reflected in the price of the good.5. a.To find the marginal revenue curve, we first derive the inverse demand curve. The intercept of the inverse demand curve on the price axis is 27. The slope of the inverse demand curve is the change in price divided by the change in quantity. For example, a decrease in price from 27 to 24 yields an increase in quantity from 0 to 2.Therefore, the slope is -32and the demand curve isP Q=-2715..The marginal revenue curve corresponding to a linear demand curve is a line with the same intercept as the inverse demand curve and a slope that is twice as steep. Therefore, the marginal revenue curve isMR = 27 - 3Q.b.The monopolist’s maximizing output occurs where marginal revenue equals marginal cost. Marginal cost is a constant $10. Setting MR equal to MC to determine the profit-maximizing quantity:27 - 3Q = 10, or Q=567..To find the profit-maximizing price, substitute this quantity into the demand equation:()().5.18$67.55.127=-=PTotal revenue is price times quantity:()().83.104$67.55.18==TRThe profit of the firm is total revenue minus total cost, and total cost is equal to average cost times the level of output produced. Since marginal cost is constant, average variable cost is equal to marginal cost. Ignoring any fixed costs, total cost is 10Q or 56.67, and profit is10483566717..$48..-=c.For a competitive industry, price would equal marginal cost at equilibrium. Setting the expression for priceequal to a marginal cost of 10:271510-=.Q , or Q =1133..Note the increase in the equilibrium quantity compared to the monopoly solution.d.The social gain arises from the elimination of deadweight loss. Since deadweight loss under monopoly is equal to the difference between the price under monopoly minus the price under competition (18.5 - 10 = 8.5) times the difference between the quantity under competition minus the quantity under monopoly (11.3 - 5.67 = 5.67) times one-half, the deadweight loss is a triangle under the demand curve:(0.5)(8.5)(5.67) = $24.10.Furthermore, consumers gain this deadweight loss plus the monopolist’s profit of $48. The monopolist’s profits are reduced to zero, and the consumer surplus increases by $72.6. a. The average revenue curve is the demand curve,P = 700 - 5Q .For a linear demand curve, the marginal revenue curve has the same intercept as the demand curve and a slope that is twice as steep:MR = 700 - 10Q .Next, determine the marginal cost of producing Q . To find the marginal cost of production in Factory 1, take the first derivative of the cost function with respect to Q :().20111Q dQQ dC = Similarly, the marginal cost in Factory 2 is().40222Q dQQ dC = Rearranging the marginal cost equations in inverse form and horizontally summing them, we obtain total marginal cost, MC T :Q Q Q MC MC MC T =+=+=12122040340, orMC Q T =403. Profit maximization occurs where MC T = MR . See the Figure 10.6.a for the profit-maximizing output for each factory, total output, and price.Figure 10.6.ab.Calculate the total output that maximizes profit, i.e., Q such that MC T = MR :40370010Q Q =-, or Q = 30. Next, observe the relationship between MC and MR for multiplant monopolies:MR = MC T = MC 1 = MC 2.We know that at Q = 30, MR = 700 - (10)(30) = 400.Therefore,MC 1 = 400 = 20Q 1, or Q 1 = 20 andMC 2 = 400 = 40Q 2, or Q 2 = 10.To find the monopoly price, P M , substitute for Q in the demand equation:This means that the demand curve becomes P = 20 - 3Q 2. With an inverse linear demand curve, we know that the marginal revenue curve has the same vertical intercept but twice the slope, or MR = 20 - 6Q 2. To determine the profit-maximizing level of output, equate MR and MC 2:20 - 6Q 2 = 10 + 5Q 2, orQ Q ==2091..Price is determined by substituting the profit-maximizing quantity into the demand equation:()3.1791.0320=-=P .8. a. Although Alcoa controlled about 90 percent of primary aluminum production in the United States, secondary aluminum production by recyclers accounted for 30 percent of the total aluminum supply. Therefore, with a higher price, a much larger proportion of aluminum supply could come from secondary sources. This assertion is true because there is a large stock of potential supply in the economy. Therefore, the price elasticity of demand for Alcoa’s primary aluminum is much higher than we would expect, given Alcoa’s domi nant position in primary aluminum production. In many applications, other metals such as copper and steel are feasible substitutes for aluminum. Again, the demand elasticity Alcoa faces might be lower than we would otherwise expect.b.While Alcoa could not raise its price by very much at any one time, the stock of potential aluminum supply is limited. Therefore, by keeping a stable high price, Alcoa could reap monopoly profits. Also, since Alcoa had originally produced the metal reappearing as recycled scrap, it would have considered the effect of scrap reclamation on future prices. Therefore, it exerted effective monopolistic control over the secondary metal supply.c.Judge Hand ruled against Alcoa but did not order it to divest itself of any of its United States production facilities. The two remedies imposed by the court were (1) that Alcoa was barred from bidding for two primary aluminum plants constructed by the government during World War II (they were sold to Reynolds and Kaiser) and (2) that it divest itself of its Canadian subsidiary, which became Alcan.9. a. Because demand (average revenue) may be described as P = 11 - Q , we know that the marginal revenue function is MR = 11 - 2Q . We also know that if average cost is constant, then marginal cost is constant and equal to average cost: MC = 6.To find the profit-maximizing level of output, set marginal revenue equal to marginal cost:11 - 2Q = 6, or Q = 2.5.That is, the profit-maximizing quantity equals 2,500 units. Substitute the profit-maximizingquantity into the demand equation to determine the price:P = 11 - 2.5 = $8.50.Profits are equal to total revenue minus total cost,π = TR - TC = (AR )(Q ) - (AC )(Q ), orπ = (8.5)(2.5) - (6)(2.5) = 6.25, or $6,250. The degree of monopoly power is given by the Lerner Index:P MC-=-=8560294... b.To determine the effect of the price ceiling on the quantity produced, substitute the ceiling price into the demandequation.7 = 11 - Q , orQ = 4,000.This quantity is the profit-maximizing level of output for the monopolist because, at that level,MR = MC .Profits are equal to total revenue minus total cost:π = (7)(4,000) - (6)(4,000) = $4,000. The degree of monopoly power is:P MC -=-=760143.. c.If the regulatory authority sets a price below $6, the monopolist would prefer to go out of business instead of produce because it cannot cover its average costs. At any price above $6, the monopolist would produce less than the 5,000 units that would be produced in a competitive industry. Therefore, the regulatory agency should set a price ceiling of $6, thus making the monopolist face a horizontal effective demand curve up to Q = 5,000. To ensure a positive output (so that the monopolist is not indifferent between producing 5,000 units and shutting down), the price ceiling should be set at $6 + δ, where δ is small.Thus, 5,000 is the maximum output that the regulatory agency can extract from the monopolistby using a price ceiling. The degree of monopoly power isP MC P -=+-=→66660δδ as δ → 0. 10.a. M MMT should offer enough t-shirts such that MR = MC . In the short run, marginal cost is the change in SRTC as the result of the production of another t-shirt, i.e.,SRMC = 5, the slope of the SRTC curve. Demand is:Q P =100002,, or, in inverse form,P = 100Q-1/2. Total revenue (PQ ) is 100Q 1/2. Taking the derivative of TR with respect to Q , MR = 50Q -1/2. Equating MR and MC to determine the profit-maximizing quantity:5 = 50Q -1/2, or Q = 100.Substituting Q = 100 into the demand function to determine price:P = (100)(100-1/2 ) = 10.The profit at this price and quantity is equal to total revenue minus total cost:π = (10)(100) - (2000 + (5)(100)) = -$1,500.Although profit is negative, price is above the average variable cost of 5 and therefore, the firm should not shut down in the short run. Since most of the firm’s costs are fixed, the firm loses $2,000 if nothing is produced. If the profit-maximizing quantity is produced, the firm loses only $1,500.b.In the long run, marginal cost is equal to the slope of the LRTC curve, which is 6.Equating marginal revenue and long run marginal cost to determine the profit-maximizing quantity:50Q -1/2 = 6 or Q = 69.44Substituting Q = 69.44 into the demand equation to determine price:P = (100)[(50/6)2] -1/2 = (100)(6/50) = 12Therefore, total revenue is $833.33 and total cost is $416.67. Profit is $416.67. The firm should remain in business.c.In the long run, MMMT must replace all fixed factors. Therefore, we can expect LRMC to be higher than SRMC .11. No, production should not shift to the Massachusetts plant, although production in the Connecticut plant should be reduced. In order to maximize profits, a mulitplant firm will schedule production at all plants so that the following two conditions are met:- Marginal costs of production at each plant are equal.- Marginal revenue of the total amount produced is equal to the marginal cost at each plant.These two rules can be summarized as MR = MC1 = MC2= MC3, where the subscript indicates the plant.The firm in this example has two plants and is in a perfectly competitive market. In a perfectly competitive market P = MR. To maximize profits, production among the plants should be allocated such that:(10,000)(n), and marginal expenditure is 10,000. Equating marginal value and marginal expenditure:30,000 - 125n = 10,000, orn = 160.13. a. To maximize profits, DD should equate marginal revenue and marginal cost. Given a demand of P = 55 - 2Q, we know that total revenue, PQ, is 55Q - 2Q2. Marginal revenue is found by taking the first derivative of total revenue with respect to Q or:MRdTRdQQ ==-554.Similarly, marginal cost is determined by taking the first derivative of the total cost function with respect to Q or:MCdTCdQQ==-2 5.Equating MC and MR to determine the profit-maximizing quantity,55 - 4Q = 2Q - 5, orQ = 10.Substituting Q = 10 into the demand equation to determine the profit-maximizing price:P = 55 - (2)(10) = $35.Profits are equal to total revenue minus total cost:π = (35)(10) - (100 - (5)(10) + 102) = $200.Consumer surplus is equal to one-half times the profit-maximizing quantity, 10, times thedifference between the demand intercept (the maximum price anyone is willing to pay) and themonopoly price:CS = (0.5)(10)(55 - 35) = $100.b.In competition, profits are maximized at the point where price equals marginal cost, where price is givenby the demand curve:55 - 2Q = -5 + 2Q, orQ = 15.Consumer surplus isCS = (0.5)(55 - 27)(14) = $196.Profits areπ = (27)(14) - (100 - (5)(14) + 142) = $152.The deadweight loss is $2.00 This is equivalent to a triangle of(0.5)(15 - 14)(27 - 23) = $2e.With a ceiling price set below the competitive price, DD will decrease its output. Equate marginal revenue and marginal cost to determine the profit-maximizing level of output:23 = - 5 + 2Q, or Q = 14.With the government-imposed maximum price of $23, profits areπ = (23)(14) - (100 - (5)(14) + 142) = $96.Consumer surplus is realized on only 14 doorsteps. Therefore, it is equal to the consumersurplus in part d., i.e. $196, plus the savings on each doorstep, i.e.,CS = (27 - 23)(14) = $56.Therefore, consumer surplus is $252. Deadweight loss is the same as before, $2.00.f.With a maximum price of only $12, output decreases even further:12 = -5 + 2Q, or Q = 8.5.Profits areπ = (12)(8.5) - (100 - (5)(8.5) + 8.52) = -$27.75.Consumer surplus is realized on only 8.5 units, which is equivalent to the consumer surplusassociated with a price of $38 (38 = 55 - 2(8.5)), i.e.,(0.5)(55 - 38)(8.5) = $72.25plus the savings on each doorstep, i.e.,(38 - 12)(8.5) = $221.Therefore, consumer surplus is $293.25. Total surplus is $265.50, and deadweight loss is $84.50.11。
平狄克《微观经济学》课后答案 3-4
CHAPTER 3CONSUMER BEHAVIORChapter 3 builds the foundation to derive the demand curve in Chapter 4. In order to understand demand theory, students must have a firm grasp of indifference curves, the marginal rate of substitution, the budget line, and optimal consumer choice. Utility theory may be discussed independently from consumer choice. Many students find utility functions to be a more abstract concept than preference relationships. However, if you plan to discuss uncertainty in Chapter 5, you will need to cover marginal utility. Even if you cover utility theory only briefly, make sure students are comfortable with the term utility because it appears frequently in Chapter 4.When introducing indifference curves, stress that physical quantities are represented on the two axes. After discussing supply and demand, students may think that price should be on the vertical axis. To develop indifference curves, start with any point in the Cartesian plane and ask for points that are more (and less) preferred. This will divide the plane into four quadrants. Then ask between which points they will be indifferent. Once students grasp the concept of preference points, introduce the notion of a “preference hill.” Using the example of a topographical map or a well-drawn three dimensional figure, point out that a three-dimensional figure is being collapsed into two dimensions.The marginal rate of substitution, MRS , is confusing to students. Some confuse the MRS with the ratio of the two quantities. If this is the case, point out that the slope is equal to the ratio of the rise, ∆Y, and the run, ∆X . This ratio is equal to the ratio of the intercepts of a line just tangent to the indifference curve. As we move along a convex indifference curve, these intercepts and the MRS change. Another problem is the terminology “of X for Y .” This is confusing because we are not substituting “X for Y ,” but Y for one unit of X . Exercise (6) discusses this point, but you may want to offer other exercises to stress it.1. What does transitivity of preferences mean?Transitivity of preferences implies that if someone prefers A to B and prefers B to C , then he orshe prefers A to C .satisfaction. This trading continues until the highest level of satisfaction is achieved.6. Explain why consumers are likely to be worse off when a product that they consume is rationed.If the maximum quantity of a good is fixed by decree and desired quantities are not available forpurchase, then there is no guarantee that the highest level of satisfaction can be achieved. Theconsumer will not be able to give up the consumption of other goods in order to obtain more of therationed good. Only if the amount rationed is greater than the desired level of consumption canthe consumer still maximize satisfaction without constraint. (Note: rationing may imply ahigher level of social welfare because of equity or fairness considerations across consumers.)7. Upon merging with West Germany’s economy, East German consumers indicated a preference for Mercedes-Benz automobiles over Volkswagen automobiles. However, when they converted their savings into deutsche marks, they flocked to Volkswagen dealerships. How can you explain this apparent paradox?Three assumptions are required to address this question: 1) that a Mercedes costs more than aVolkswagen; 2) that the East German consumers’ utility function comprises two goods,automobiles and all other goods evaluated in deutsche marks; and 3) that East Germans haveincomes. Based on these assumptions, we can surmise that while once-East German consumersmay prefer a Mercedes to a Volkswagen, they either cannot afford a Mercedes or they prefer abundle of other goods plus a Volkswagen to a Mercedes alone.8. Describe the equal marginal principle. Explain why this principle may not hold if increasing marginal utility is associated with the consumption of one or both goods.The equal marginal principle states that the ratio of the marginal utility to price must be equalacross all goods to obtain maximum satisfaction. This explanation follows from the same logicexamined in Review Question 5. Utility maximization is achieved when the budget is allocatedso that the marginal utility per dollar of expenditure is the same for each good.If marginal utility is increasing, the consumer maximizes satisfaction by consuming ever largeramounts of the good. Thus, the consumer would spend all income on one good, assuming aconstant price, resulting in a corner solution. With a corner solution, the equal marginalprinciple cannot hold.9. What is the difference between ordinal utility and cardinal utility? Explain why the assumption of cardinal utility is not needed in order to rank consumer choices.Ordinal utility implies an ordering among alternatives without regard for intensity of preference.For example, the consumer’s first choice is preferred to their second choice. Cardinal utilityimplies that the intensity of preferences may be quantified. An ordinal ranking is all that isneeded to rank consumer choices. It is not necessary to know how intensely a consumer prefersbasket A over basket B; it is enough to know that A is preferred to B.10. The price of computers has fallen substantially over the past two decades. Use this drop in price to explain why the Consumer Price Index is likely to substantially understate the cost-of-living index for individuals who use computers intensively.The consumer price index measures the changes in the weighted average of the prices of thebundle of goods purchased by consumers. The weights equal the share of consumer's expenditureson all of the goods in the bundle. A base year is chosen, and the weights for that year are used tocompute the CPI in that and subsequent years. When the price of a good falls substantially then aconsumer will substitute towards that good, altering the share of that consumer's income spent oneach good. By using the base year's weights the CPI does not take into account that large pricechanges alter these expenditure shares, and so gives an inaccurate measure of changes in the costof living.For example, assume Fred spends 10% of his income on computers in 1970, and that Fred'sexpenditure shares in 1970 were used as the weights to calculate Fred's CPI in subsequent years.If Fred's demand for computers was inelastic, then reductions in the price of computers (relativeto other goods) would reduce the share of his income spent on computers. After 1970 a CPI thatused Fred's 1970 expenditure shares as weights would give a 10% weight to the falling price ofcomputers, even though Fred spent less that 10% of his income on computers. So long as theprices of other goods rose, or fell less than 10%, then the CPI gives too little weight to the changesin the prices of other goods, and understates the changes in Fred's cost of living.1. In this chapter, consumer preferences for various commodities did not change during the analysis. Yet in some situations, preferences do change as consumption occurs. Discuss why and how preferences might change over time with consumption of these two commodities:a. cigarettesThe assumption that preferences do not change is a reasonable one if choices are independentacross time. It does not hold, however, when “habit-forming” or addictive behavior is involved, asin the case of cigarettes: the consumption of cigarettes in one period influences their consumptionin the next period.b. dinner for the first time at a restaurant with a special cuisineWhile there may not be anything physically addictive in dining at new and different restaurants, one can become better informed about a particular restaurant. One may enjoy choosing more new and different restaurants, or one may be tired of choosing another new and different place to4.a.c. tothis graphically?, the quantity of butter by B, the Let Bill’s income be represented by Y, the price of butter by PB, and the quantity of margarine by M. Then the general form of the price of margarine by PMbudget constraint is:5.the their a.c. If both Smith and Jones pay the same prices for their refreshments, will their marginal rates ofsubstitution of alcoholic for nonalcoholic drinks be the same or different? Explain.In order to maximize utility, the consumer must consume quantities such that the MRS betweenany two commodities is equal to the ratio of prices. If Smith and Jones are rational consumers,their MRS must be equal because they face the same market prices. But because they havedifferent preferences, they will consume different amounts of the two goods, alcoholic andnonalcoholic. At those different levels, however, their MRS are equal.6. Anne is a frequent flyer whose fares are reduced (through coupon giveaways) by 25 percent after she flies 25,000 miles a year, and then by 50 percent after she flies 50,000 miles. Can you graph the budget line that Anne faces in making her flight plans for the year?In Figure 3.6, we plot miles flown, M , against all other goods, G , in dollars. The budgetconstraint is:Y = P M M + P G G , or.⎪⎪⎭⎫ ⎝⎛-=G M G P P M P Y G The slope of the budget line is -P P M G. In this case, the price of miles flown changes as the number of miles flown changes, so the budget curve is kinked at 25,000 and at 50,000 miles. Suppose P M is $1 per mile for less than or equal to 25,000 miles. Then P M = $0.75 for 25,000 < M ≥ 50,000 and P M = $0.50 for M > 50,000. Also, let P G = $1.00. Then the slope of the budget line from A to B is -1, the slope of the budget line from B to C is -0.75, and the slope of the budget line from B to D is -0.5.8. Suppose that Samantha and Jason both spend $24 per week on video and movie entertainment.U = 12 U = 24Food Clothing Food Clothing 1.0 12.0 1.0 24.01.5 8.02.0 12.02.0 6.03.0 8.012 = 1F + 3C , or ⎪⎪⎭⎝-=34.See Figure 3.10.a.c. What is the utility-maximizing choice of food and clothing? (Hint: Solve the problemgraphically.)The highest level of satisfaction occurs where the budget line is tangent to the highestindifference curve. In Figure 3.10.a this is at the point F = 6 and C = 2. To check this answer,note that it exhausts Jane’s income, 12 = 6P F + 2P C . Also, this bundle yields a satisfaction of 12,as (6)(2) = 12. See Figure 3.10.a.d. What is the marginal rate of substitution of food for clothing when utility is maximized?At the utility-maximizing level of consumption, the slope of the indifference curve is equal to theslope of the budget constraint. Since the MRS is equal to the negative slope of the indifferencecurve, the MRS in this problem is equal to one-third. Thus, Jane would be willing to give upone-third of a unit of clothing for one unit of food.e. Suppose that Jane buys 3 units of food and 3 units of clothing with her $12 budget. Would hermarginal rate of substitution of food for clothing be greater or less than 1/3? Explain.If Jane buys 3 units of food for $1.00 per unit and 3 units of clothing for $3.00 per unit, she wouldspend all her income. However, she would obtain a level of satisfaction of only 9, whichrepresents a sub-optimal choice. At this point, the MRS is greater than one-third, and thus, atthe prices she faces, she would welcome the opportunity to give up clothing to get more food. Sheis willing to trade clothing for food until her MRS is equal to the ratio of prices. See Figure3.10.c.Figure 3.10.c11. The utility that Meredith receives by consuming food F and clothing C is given by u(F,C) = FC. Suppose that Meredith’s income in 1990 is $1,200 and the prices of food and clothing are $1 per unit for each. However, by 1995 the price of food has increased to $2 and the price of clothing to $3. Let 100 represent the cost of living index for 1990. Calculate the ideal and the Laspeyres cost-of-living index for Meredith for 1995. (Hint: Meredith will spend equal amounts on food and clothing with these preferences.)Laspeyres IndexThe Laspeyres index represents how much more Meredith would have to spend in 1995 versus 1990 ifshe consumed the same amounts of food and clothing in 1995 as she did in 1990. That is, the Laspeyresindex for 1995 (L) is given by:L = 100 (Y ')/Ywhere Y’ represents the amount Meredith would spend at 1995 prices consuming the same amount offood and clothing as in 1990: Y ' = P 'F F + P 'C C = 2F + 3C, where F and C represent the amounts of foodand clothing consumed in 1990.We thus need to calculate F and C, which make up the bundle of food and clothing which maximizesMeredith’s utility given 1990 prices and her income in 1990. Use the hint to simplify the problem:Since she spends equal amounts on both goods, P F F = P C C. Or, you can derive this same equationmathematically: With this utility function, MU C = ∆U/∆C = F, and MU F = ∆U/∆F = C. To maximizeutility, Meredith chooses a consumption bundle such that MU F /MU C = P F /P C , which again yields P F F =P C C.From the budget constraint, we also know that:P F F +P C C = YCombining these two equations and substituting the values for the 1990 prices and income yields thesystem of equations:C = F and C + F = 1,200Solving these two equations, we find that:C = 600 and F = 600Therefore, the Laspeyres cost-of-living index is:L = 100(2F + 3C)/Y = 100[(2)(600) + (3)(600)]/1200 = 250Ideal IndexThe ideal index represents how much more Meredith would have to spend in 1995 versus 1990 if sheconsumed amounts of food and clothing in 1995 which would give her the same amount of utility as shehad in 1990. That is, the ideal index for 1995 (I) is given by:I = 100(Y'')/Y, where Y'' = P'F F + P'C C' = 2F' + 3C'where F' and C' are the amount of food and clothing which give Meredith the same utility as she had in1990. F' and C' must also be such that Meredith spends the least amount of money at 1995 prices toattain the 1990 utility level.The bundle (F',C') will be on the same indifference curve as (F,C) and the indifference curve at this point will be tangent to a budget line with slope -(P'F /P'C ), where P'F and P'C are the prices of food and clothing in 1995. Since Meredith spends equal amounts on the two goods, we know that 2F' = 3C'. Since this bundle lies on the same indifference curve as the bundle F = 600, C = 600, we also know that F'C' = (600)(600).Cslope 1P slope F C =-H K slope slope F C =-'H KFigure 3.11Solving for F' yields:F'[(2/3)F'] = 360,000 or F' =[(/),)]32360000 = 734.8From this, we obtain C':C' = (2/3)F' = (2/3)734.8 = 489.9We can now calculate the ideal index: I = 100(2F' + 3C')/Y = 100[2(734.8) + (3)(489.9)]/1200 = 244.9CHAPTER 4INDIVIDUAL AND MARKET DEMANDChapter 4 relies on two important ideas from Chapter 3: the influence of price and income changes on the budget line and optimal consumer choice. The chapter focuses on price changes, individual demand, market demand, demand elasticity, and consumer surplus. These concepts are crucial to understanding the application of demand and supply analysis in Chapter 9 as well as the discussion of market failure in Parts III and IV. Chapter 4 also discusses the derivation of the individual’s demand curve with a discussion of substitution and income effects. The analytical tools students learn in this chapter will be important for the discussion of factor supply and demand in Chapter 14.When discussing the derivation of demand, review how the budget curve pivots around an intercept as price changes and how optimal quantities change as the budget line pivots. Once students understand the effect of price changes on consumer choice, they can grasp the derivation of the price consumption path and the individual demand curve. Remind students that the price a consumer is willing to pay is a measure of the marginal benefit of consuming another unit.When covering the aggregation of individual demands, stress that this is equivalent to the summation of individual demand curves horizontally. Students might think that they can add linear demand functions, e.g., add Q P =-1 plus Q P =-23 to arrive at Q P =-35 or 223Q P =-. Students must be reminded, instead, to write the demand curve in inverse form, with price as a function of quantity, and then add. Thus, we add P = 1 - Q to P = 1 - 2Q to obtain P = 2 - 3Q .Price elasticity of demand and consumer surplus are referred to throughout the text, but the mathematics of price elasticity of demand is difficult for many students. Before discussing the algebra, encourage students to develop an intuitive grasp of elasticity as a measure of the sensitivity of the quantity demanded to changes in price.The easiest algebraic representation of elasticity is %%∆∆QP. As you expand on this expression, make sure thatstudents can distinguish between the slope of a line and an elasticity at each point. One effective teaching method is using a linear demand curve to show that while the slope is constant, the elasticity changes throughout the range of prices. The text relies on this relationship in the discussion of the monopolist’s determination of the profit-maximizing quantity in Chapter 10. The exercises given here are progressive in their difficulty, i.e., the last exercise is much harder than the first. Exercises (1) and (7) assume student understanding of demand elasticity, and a grasp of income elasticity is needed for Exercise (9).Although this chapter introduces consumer surplus, it is not extensively discussed until Chapter 9; producer surplus is covered in Chapter 8. If you postpone the discussion of consumer surplus, do not assign Exercise (4). Once students understand consumer surplus, they will find it to be an extremely useful tool. See Example 4.5.Section 4.2 discusses income and substitution effects. An understanding of these effects is aided by the discussion of normal and inferior goods. This is also a good time to reinforce the concept of relative prices, i.e., a decrease in the price of one good increases the relative price of the other good. Giffen goods, while infrequently encountered, provide a way to discuss the importance of income and substitution effects.Finally, there are other special topics in this chapter and its Appendix. An application of network externalities is given in Example 4.5. The first part of Section 4.6, “Empirical Estimation of Demand,” is straightforward, particularly if you have covered the forecasting section of Chapter 2. However, the l ast part, “The Form of the Demand Relationship,” is difficult for students who do not understand logarithms. The Appendix is intended for students with a background in calculus.1.How is an individual demand curve different from a market demand curve? Which curve is likely to be more price elastic? (Hint: Assume that there are no network externalities.)The market demand curve is the horizontal summation of the individual demand curves. Thegraph of market demand shows the relation between each price and the sum of individualquantities. Because price elasticities of demand may vary by individual, the price elasticity ofdemand is likely to be greater than some individual price elasticities and less than others.2.Is the demand for a particular brand of product, such as Head skis, likely to be more price elastic or price inelastic than the demand for the aggregate of all brands, such as downhill skis? Explain.Individual brands compete with other brands. If the two brands are similar, a small change inthe price of one good will encourage many consumers to switch to the other brand. Becausesubstitutes are readily available, the quantity response to a change in one brand’s price is moreelastic than the quantity response for all brands. Thus, the demand for Head skis is more elasticthan the demand for downhill skis.3.Tickets to a rock concert sell for $10. But at that price, the demand is substantially greater than the available number of tickets. Is the value or marginal benefit of an additional ticket greater than, less than, or equal to $10? How might you determine that value?If, at $10, demand exceeds supply, then consumers are willing to bid up the market price to a levelwhere the quantity demanded is equal to the quantity supplied. Since utility-maximizingconsumers must be willing to pay more than $10, then the marginal increase in satisfaction(value) is greater than $10. One way to determine the value of tickets would be to auction off ablock of tickets. The highest bid would determine the value of the tickets.4.Suppose a person allocates a given budget between two goods, food and clothing. If food is an inferior good, can you tell whether clothing is inferior or normal? Explain.If an individual consumes only food and clothing, then any increase in income must be spent oneither food or clothing (Hint: we assume there are no savings). If food is an inferior good, then,as income increases, consumption falls. With constant prices, the extra income not spent on foodmust be spent on clothing. Therefore, as income increases, more is spent on clothing, i.e. clothingis a normal good.5. Which of the following combinations of goods are complements and which are substitutes? Could they be either in different circumstances? Discuss.a. a mathematics class and an economics classIf the math class and the economics class do not conflict in scheduling, then the classes could beeither complements or substitutes. The math class may illuminate economics, and theeconomics class can motivate mathematics. If the classes conflict, they are substitutes.b. tennis balls and a tennis racketTennis balls and a tennis racket are both needed to play a game of tennis, thus they arecomplements.c. steak and lobsterFoods can both complement and substitute for each other. Steak and lobster can compete, i.e., besubstitutes, when they are listed as separate items on a menu. However, they can also functionas complements because they are often served together.d. a plane trip and a train trip to the same destinationTwo modes of transportation between the same two points are substitutes for one another.e. bacon and eggsBacon and eggs are often eaten together and are, therefore, complementary goods. Byconsidering them in relation to something else, such as pancakes, bacon and eggs can function assubstitutes.6.Which of the following events would cause a movement along the demand curve for U.S.-produced clothing, and which would cause a shift in the demand curve?a. the removal of quotas on the importation of foreign clothesThe removal of quotas will shift the demand curve inward for domestically-produced clothes,because foreign-produced goods are substitutes for domestically-produced goods. Both theequilibrium price and quantity will fall as foreign clothes are traded in a free marketenvironment.b. an increase in the income of U.S. citizensWhen income rises, expenditures on normal goods such as clothing increase, causing the demandcurve to shift out. The equilibrium quantity and price will increase.c. a cut in the industry’s costs of producing domestic clothes that is passed on to the market inthe form of lower clothing pricesA cut in an industry’s costs will shift the supply curve out. The equilibrium price an d quantitywill increase.7. For which of the following goods is a price increase likely to lead to a substantial income (as well as substitution) effect?a. saltSmall income effect, small substitution effect: The amount of income that is spent on salt isrelatively small, but since there are few substitutes for salt, consumers will not readily substituteaway from it. As the price of salt rises, real income will fall only slightly, thus leading to a smalldecline in consumption.b. housingLarge income effect, no substitution effect: The amount of income spent on housing is relativelylarge for most consumers. If the price of housing were to rise, real income would be reducedsubstantially, thereby reducing the consumption of all other goods. However, consumers wouldfind it impossible to substitute for housing, in general.c. theater ticketsSmall income effect, large substitution effect: The amount of income that is spent on theatertickets is relatively small, but consumers can substitute away from the theater tickets by choosingother forms of entertainment (e.g., television and movies). As the price of theater tickets rises,real income will fall only slightly, thus leading to a small decline in consumption.d. foodLarge income effect, no substitution effect: As with housing, the amount of income spent on food isrelatively large for most consumers. Price increases for food will reduce real incomesubstantially, thereby reducing the consumption of all other commodities. Although consumerscan substitute out of particular foods, they cannot substitute out of food in general.8. Suppose that the average household in a state consumes 500 gallons of gasoline per year. A 10-cent gasoline tax is introduced, coupled with a $50 annual tax rebate per household. Will the household be better or worse off after the new program is introduced?If the household does not change its consumption of gasoline, it will be unaffected by thetax-rebate program. It still gets 500 gallons of gasoline. To the extent that the householdreduces its gas consumption through substitution, it must be better off.9. Which of the following three groups is likely to have the most, and which the least, price-elastic demand for membership in the Association of Business Economists?a. studentsThe major difference among the groups is the level of income. We know that if the consumptionof a good constitutes a large percentage of an individual’s income, then the demand for the goodwill be relatively elastic. If we assume that a membership in the Association of BusinessEconomists is likely to be a large expenditure for students, we may conclude that the demand willbe relatively elastic for this group.b. junior executivesThe level of income for junior executives will be larger than that of students, but smaller thanthat of senior executives. Therefore, the demand for a membership for this group will be lesselastic than that of the students but more elastic than that of the senior executives.c. senior executivesThe high earnings among senior executives will result in a relatively inelastic demand formembership.1. The ACME corporation determines that at current prices the demand for its computer chips has a price elasticity of -2 in the short run, while the price elasticity for its disk drives is -1.a. If the corporation decides to raise the price of both products by 10 percent, what will happento its sales? To its sales revenue?We know the formula for the elasticity of demand is:EQP P=%%∆∆.For computer chips, EP= -2, so a 10 percent increase in price will reduce the quantity sold by 20percent. For disk drives, EP= -1, so a 10 percent increase in price will reduce sales by 10 percent.Sales revenue is equal to price times quantity sold. Let TR1 = P1Q1be revenue before the pricechange and TR2 = P2Q2be revenue after the price change.For computer chips:∆TR cc = P2Q2 - P1Q1∆TR cc= (1.1P1 )(0.8Q1 ) - P1Q1 = -0.12P1Q1, or a 12 percent decline.For disk drives:∆TR dd = P2Q2 - P1Q1∆TR dd = (1.1P1 )(0.9Q1 ) - P1Q1 = -0.01P1Q1, or a 1 percent decline.Therefore, sales revenue from computer chips decreases substantially, -12 percent, while the salesrevenue from disk drives is almost unchanged, -1 percent.b. Can you tell from the available information which product will generate the most revenue forthe firm? If yes, why? If not, what additional information would you need?No. Although we know the responsiveness of demand to changes in price, we need to know bothquantities and prices of the products to determine total sales revenue.2. Refer to Example 4.3 on the aggregate demand for wheat. From 1981 to 1990, domestic demand grew in response to growth in U.S. income levels. As a rough approximation, the domestic demand curve in 1990 was QDD= 1200 - 55P. Export demand, however, remained about the same, due to。
平狄克微观经济学答案——第8章 利润最大化和竞争性供给
第八章利润最大化和竞争性供给教学笔记这一章确定了追求利润最大化的厂商的行为动机，揭示了这些厂商在竞争性市场的相互影响和作用。
这一章的每一节都很重要，它们构建了对竞争性市场供给一方的彻底完全的认识。
在学习这本教科书的第三部分之前，建立这样一个基础是非常必要的。
虽然这一章的材料都写得很清楚易懂，但是学生可能还是会对有些概念、思想感到很难理解，比如说那些有关厂商应该怎样选择最佳生产数量的思想、有关厂商怎样应用我们前面学习过的成本曲线的思想，等等。
这里有一个讲课的建议：花些时间研究与这一章的最后部分的习题中用到的表格相类似的表格。
研究一些与此类表格有关的例题对于学生理解不同类型的成本，以及相应的厂商的最佳产量是有帮助的。
8.1节确定了完全竞争市场的三个基本假设，8.2节对“厂商以利润最大化为经营目标”这一假设进行了讨论。
8.3节和8.5节对厂商的供给曲线进行了推导，8.1节和8.2节为8.3节、8.5节中供给曲线的推导打下了基础。
8.3节推导出一个一般性的结论：只要边际收入等于边际成本，厂商就应当生产。
这一节接下来确定了完全竞争（一个特殊的案例）的条件之一：价格等于边际收入，这个结论是8.1节中“接受价格”这个假设的直接的逻辑结果。
如果你的学生掌握微积分，那么通过对利润函数关于产量q求微分，可以导出边际成本与边际收入相等。
如果你的学生还没有掌握微积分，那么可以通过对数据表格的多加研究来理解当边际收入和边际成本相等时厂商能达到利润最大化目标这个结论。
这里有一点需要强调：完全竞争市场上，每个厂商只能通过产量的变化而不能通过价格的变化来取得最大利润。
为了正确理解完全竞争市场，我们在提出有关完全竞争市场的假设之前，也要对卖方垄断、寡头卖方垄断和垄断性竞争有一定的了解。
将讨论限定一个专门的范围，这个范围包括确定一个行业里有多少厂商、这个行业是否有进入壁垒、各个厂商的产品是否存在差异，以及行业里每个厂商对其他厂商对于其价格、数量方面的决策的反应做出的假设。
(整理)平狄克微观经济学答案第14-16章
第十四章生产性要素市场习题简解１、答：在竞争性要素市场有ＭＲＰL=ＭＰL*Ｐ，在垄断市场有P>MR，所以ＭＰL*Ｐ>ＭＲＭ*ＰL，劳动的需求曲线是关于要素价格W，要素需求L是要素价格的涵数。
于是其弹性为Ｅdl＝dL/dW*W/L，厂商为了追求利润最大化总有MRP=W，而垄断厂商的ＭＲＰ（垄）<ＭＲＰ（竞），所以ＭＲＰ（垄）雇用工人的工资W小于竞争性厂商雇用工人的工资，即所以它比竞争性生产时弹性小。
２、我们知道劳动的供给曲线是向后弯曲的，它表示劳动的供给量起初随工资率的提高而增加，而工资率提高到一定程度后，供给量会随W提高而减少，从而使供给曲线呈后弯曲形状。
下面我们可以用收入效应和替代效应对此种情况加以分析，我们将一天分成工作时间和闲瑕时间，随着工资率的提高，闲瑕的价格也提高。
替代效应是因为较高的闲瑕价格鼓励工人用工作代替闲瑕。
收入效应是因为较高的工资率提高了工人的购买力。
用下图分析为：Ｒ（其中替代效应小于收入效应，向后弯曲）ＰＨ３、（1）何为引致需求，厂商对生产要素的需求是从消费者对产品的直接需求中派生出来的，即派生需求或引致需求。
（2）电脑公司的主要任务是销售电脑以获得利润，而在销售电脑时，售后服务也是同样重要的。
必须为客户组装各种程序，即软件系统需要雇用电脑编程人员。
因此，电脑公司对电脑编程人员的需求是引致需求。
４、垄断性雇主即买方垄断，也就是说厂商在要素市场（作为要素的买方）是垄断者，但在产品市场上是完全竞争者，ＭＥ为边际支出，ＭＥ＝ＭＣ*ＭＰ，在完全竞争市场中ＭＥ＝Ｗ且Ｗ（Ｌ）＝Ｗ为要素的供给的曲线，ＭＥ＝ＭＲＰ为买方垄断厂商的要素使用原则，从而Ｅ点为垄断厂高均衡点，Ｂ点为完全竞争市场的均衡点。
由图可知：Ｌ0<Ｌ1，Ｗ0<Ｗ2，买方垄断厂商无需求曲线，所以Ｗ0为均衡价格。
所以，竞争性雇主雇用较多的工人且支付较多的工资。
WMEW1 EW2 W(L)W0 A BMRP=DL0 L1 L５、摇滚乐手的供给是缺乏弹性的，各个摇滚乐手的演唱风格不同，消费者独特的喜好，对于摇滚乐手的票价的不同其消费数量的变化不大，所以，摇滚乐手的演唱属于缺乏弹性的产品。
平狄克《微观经济学》课后答案 7-8
CHAPTER 7THE COST OF PRODUCTIONIn this chapter, it is easy for the students to concentrate too much on definitions and geometry and lose focus on the economics. Therefore, keep in mind the key concepts: opportunity cost, short-run average and marginal cost, cost minimization, and long-run average cost. These concepts can be illuminated with the supplementary material provided at the end of the chapter, which includes sections on economies of scope, learning curves, and estimating and predicting costs. The Appendix presents the calculus of constrained optimization, as applied to cost minimization. All exercises involve some algebra or geometry: Exercises (12) and (13) are time consuming, but rewarding.Opportunity cost is the conceptual base of this chapter. While most students think of costs in accounting terms, they must develop an understanding of the distinction between accounting, economic, and opportunity costs. One source of confusion is the opportunity cost of capital, i.e., why the rental rate on capital must be considered explicitly by economists. It is important, for example, to distinguish between the purchase price of capital equipment and the opportunity cost of using the equipment. The opportunity cost of a person’s tim e also leads to some confusion for students.Following the discussion of opportunity cost, the chapter diverges in two directions: one path introduces types of cost and cost curves, and the other focuses on cost minimization. Both directions converge with the discussion of long-run average cost.The geometry of total, fixed, variable, average, and marginal costs can prove to be tedious. An emphasis on the following issues helps students master this topic: 1) the relationship between the production function, diminishing returns in the short run, input prices, and the shapes of the various cost curves; 2) the distinction between total, average, and marginal; and 3) the reasonableness of the assumption of constant input prices (note that this assumption w ill be relaxed in Chapter 10’s discussion of monopsony). The determination of the cost-minimizing quantity is crucial to understanding Chapters 8 and 10. The concept of duality (minimizing cost subject to a given level of production) is equivalent to maximizing output subject to a given level of total cost) clarifies this concept for students.A clear understanding of short-run cost and cost minimization is necessary for the derivation of long-run average cost. With long-run costs, stress that firms are operating on short-run cost curves at each level of the fixed factor and that long-run costs do not exist separately from short-run costs. Exercise (6) illustrates the relationship between long-run cost and cost minimization, with an emphasis on the importance of the expansion path. Stress the connection between the shape of a long-run cost curve and returns to scale. While Section 7.7 is starred, it does not require calculus. Example 7.5 “Cost Functions for Electric Power,” gives students another vie w of long-run average cost and allows for discussion of minimum efficient scale, an important determinant of industry structure.1. A firms pays its accountant an annual retainer of $10,000. Is this an explicit or implicit cost?Explicit costs are actual outlays. They include all costs that involve a monetary transaction.An implicit cost is an economic cost that does not necessarily involve a monetary transaction, butstill involves the use of resources. When a firm pays an annual retainer of $10,000, there is amonetary transaction. The accountant trades his or her time in return for money. Therefore,an annual retainer is an explicit cost.2. The owner of a small retail store does her own accounting work. How would you measure the opportunity cost of her work?Opportunity costs are measured by comparing the use of a resource with its alternative uses.The opportunity cost of doing accounting work is the time not spent in other ways, i.e., time suchas running a small business or participating in leisure activity. The economic cost of doingaccounting work is measured by computing the monetary amount that the time would be worth inits next best use.3. Suppose a chair manufacturer finds that the marginal rate of technical substitution of capital for labor in his production process is substantially greater than the ratio of the rental rate on machinery to the wage rate for assembly-line labor. How should he alter his use of capital and labor to minimize the cost of production?To minimize cost, the manufacturer should use a combination of capital and labor so the rate atwhich he can trade capital for labor in his production process is the same as the rate at which hecan trade capital for labor in external markets. The manufacturer would be better off if heincreased his use of capital and decreased his use of labor, decreasing the marginal rate oftechnical substitution, MRTS. He should continue this substitution until his MRTS equals theratio of the rental rate to the wage rate.4. Why are isocost lines straight lines?The isocost line represents all possible combinations of labor and capital that may be purchasedfor a given total cost. The slope of the isocost line is the ratio of the input prices of labor andcapital. If input prices are fixed, then the ratio of these prices is clearly fixed and the isocost lineis straight. Only when the ratio or factor prices change as the quantities of inputs change is theisocost line not straight.5. If the marginal cost of production is increasing, does this tell you whether the average variable cost is increasing or decreasing? Explain.Marginal cost can be increasing while average variable cost is either increasing or decreasing. Ifmarginal cost is less (greater) than average variable cost, then each additional unit is adding less(more) to total cost than previous units added to the total cost, which implies that the AVCdeclines (increases). Therefore, we need to know whether marginal cost is greater than averagecost to determine whether the AVC is increasing or decreasing.6. If the marginal cost of production is greater than the average variable cost, does this tell you whether the average variable cost is increasing or decreasing? Explain.If the average variable cost is increasing (decreasing), then the last unit produced is adding more(less) to total variable cost than the previous units did, on average. Therefore, marginal cost isabove (below) average variable cost. If marginal cost is above average variable cost, averagevariable cost is also increasing.7. If the firm’s average cost curves are U-shaped, why does its average variable cost curve achieve its minimum at a lower level of output than the average total cost curve?Total cost is equal to fixed plus variable cost. Average total cost is equal to average fixed plusaverage variable cost. When graphed, the difference between the U-shaped total cost andaverage variable cost curves is the average fixed cost curve. If fixed cost is greater than zero, theminimum of average variable cost must be less than the minimum average total cost.8. If a firm enjoys increasing returns to scale up to a certain output level, and then constant returns to scale, what can you say about the shape of the firm’s long-run average cost curve?When the firm experiences increasing returns to scale, its long-run average cost curve isdownward sloping. When the firm experiences constant returns to scale, its long-run averagecost curve is horizontal. If the firm experiences increasing returns to scale, then constantreturns to scale, its long-run average cost curve falls, then becomes horizontal.9. How does a change in the price of one input change the firm’s long-run expansion path?The expansion path describes the combination of inputs for which the firm chooses to minimizecost for every output level. This combination depends on the ratio of input prices: if the price ofone input changes, the price ratio also changes. For example, if the price of an input increases,less of the input may be purchased for the same total cost. The intercept of the isocost line onthat input’s axis moves closer to the origin. Also, the slope of the isocost line, the price ratio,changes. As the price ratio changes, the firm substitutes away from the now more expensiveinput toward the cheaper input. Thus, the expansion path bends toward the axis of the nowcheaper input. See Exercise (7.6).10. Distinguish between economies of scale and economies of scope. Why can one be present without the other?Economies of scale refer to the production of one good and occur when proportionate increases inall inputs lead to a more-than-proportionate increase in output. Economies of scope refer to theproduction of more than one good and occur when joint output is less costly than the sum of thecosts of producing each good or service separately. There is no direct relationship betweenincreasing returns to scale and economies of scope, so production can exhibit one without theother. See Exercise (13) for a case with constant product-specific returns to scale andmultiproduct economies of scope.1. Assume a computer firm’s marginal costs of production are constant at $1,000 per computer. However, the fixed costs of production are equal to $10,000.a. Calculate the firm’s average variable cost and average total cost curves.The variable cost of producing an additional unit, marginal cost, is constant at $1,000, so theaverage variable cost is constant at $1,000, ()000,1$000,1$=QQ . Average fixed cost is $10,000Q. Average total cost is the sum of average variable cost and average fixed cost: ATC Q=+$1,$10,.000000 b. If the firm wanted to minimize the average total cost of production, would it choose to be verylarge or very small? Explain.The firm should choose a very large output because average total cost decreases with increase inQ . As Q becomes infinitely large, ATC will equal $1,000.2. If a firm hires a currently unemployed worker, the opportunity cost of utilizing t he worker’s service is zero. Is this true? Discuss.From the worker’s perspective, the opportunity cost of his or her time is the time not spent inother ways, including time spent in personal or leisure activities. Certainly, the opportunity costof hiring an unemployed mother of pre-school children is not zero! While it might be difficult toassign a monetary value to the time of an unemployed worker, we can not conclude that it is zero.From the perspective of the firm, the opportunity cost of hiring the worker is not zero, and thefirm could purchase a piece of machinery rather than hiring the worker.3.a. Suppose that a firm must pay an annual franchise fee, which is a fixed sum, independent of whether it produces any output. How does this tax aff ect the firm’s fixed, marginal, and average costs?Total cost, TC , is equal to fixed cost, FC , plus variable cost, VC . Fixed costs do not vary with thequantity of output. Because the franchise fee, FF , is a fixed sum, the firm’s fixed costs increaseby this fee. Thus, average cost, equal toFC VC Q +, and average fixed cost, equal to FC Q , increase by the average franchise fee FF Q. Note that the franchise fee does not affect average variable cost. Also, because marginal cost is the change in total cost with the production of anadditional unit and because the fee is constant, marginal cost is unchanged.3.b. Now suppose the firm is charged a tax that is proportional to the number of items it produces. Ag ain, how does this tax affect the firm’s fixed, marginal, and average costs?Let t equal the per unit tax. When a tax is imposed on each unit produced, variable costsincrease by tQ . Average variable costs increase by t , and because fixed costs are constant,average (total) costs also increase by t . Further, because total cost increases by t with eachadditional unit, marginal costs increase by t .4. A recent issue of Business Week reported the following:During the recent auto sales slump, GM, Ford, and Chrysler decidedit was cheaper to sell cars to rental companies at a loss than to lay offworkers. That’s because closing and reopening plants is expensive,partly because the auto makers’ current union contracts obligatethem to pay many wor kers even if they’re not working.When the article discusses selling cars “at a loss,” is it referring to accountingprofit or economic profit? How will the two differ in this case? Explainbriefly.When the article refers to the car companies selling at a loss, it is referring to accounting profit.The article is stating that the price obtained for the sale of the cars to the rental companies was less than their accounting cost. Economic profit would be measured by the difference of theprice with the opportunity cost of the cars. This opportunity cost represents the market valueof all the inputs used by the companies to produce the cars. The article mentions that the carcompanies must pay workers even if they are not working (and thus producing cars). Thisimplies that the wages paid to these workers are sunk and are thus not part of the opportunitycost of production. On the other hand, the wages would still be included in the accountingcosts. These accounting costs would then be higher than the opportunity costs and wouldmake the accounting profit lower than the economic profit.5. A chair manufacturer hires its assembly-line labor for $22 an hour and calculates that the rental cost of its machinery is $110 per hour. Suppose that a chair can be produced using 4 hours of labor or machinery in any combination. If the firm is currently using 3 hours of labor for each hour of machine time, is it minimizing its costs of production? If so, why? If not, how can it improve the situation?If the firm can produce one chair with either four hours of labor or four hours of capital,machinery, or any combination, then the isoquant is a straight line with a slope of -1 andintercept at K = 4 and L = 4, as depicted in Figure 7.5.The isocost line, TC = 22L + 110K has a slope of -=-2211002. when plotted with capital on the vertical axis and has intercepts at K TC =110 and L TC =22. The cost minimizing point is a corner solution, where L = 4 and K = 0. At that point, total cost is $88.6. Suppose the economy takes a downturn, and that labor costs fall by 50 percent and are expected to stay at that level for a long time. Show graphically how this change in the relative price of labor and capital affects the firm’s expansion path.Figure 7.6 shows a family of isoquants and two isocost curves. Units of capital are on the verticalaxis and units of labor are on the horizontal axis. (Note: In drawing this figure we have assumedthat the production function underlying the isoquants exhibits constant returns to scale, resultingin linear expansion paths. However, the results do not depend on this assumption.)If the price of labor decreases while the price of capital is constant, the isocost curve pivotsoutward around its intersection with the capital axis. Because the expansion path is the set ofpoints where the MRTS is equal to the ratio of prices, as the isocost curves pivot outward, theexpansion path pivots toward the labor axis. As the price of labor falls relative to capital, thefirm uses more labor as output increases.business when costs are cheaper and discourage off-peak business when costs are higher.Do you follow the consultant’s advice? Discuss.The consultant does not understand the definition of average cost. Encouraging ridership always decreases average costs, peak or off-peak. If ridership falls to 10, costs climb to $3.00 per rider. Further, during rush hour, the buses are full. How could more people get on? Instead, encourage passengers to switch from peak to off-peak times, for example, by charging higher prices during peak periods.MC 2 is the marginal cost of refining distillate up to the capacity constraint, Q 2. The shape of thetotal marginal cost curve is horizontal up to the lower capacity constraint. If the capacityconstraint of the distilling unit is lower than that of the hydrocracking unit, MC T is vertical at Q 1.If the capacity constraint of the hydrocracking unit is lower than that of the distilling unit, MC T isvertical at Q 2.9. You manage a plant that mass produces engines by teams of workers using assembly machines. The technology is summarized by the production function.Q 4 KLwhere Q is the number of engines per week, K is the number of assembly machines, and L is the number of labor teams. Each assembly machine rents for r = $12,000 per week and each team costs w = $3,000 per week. Engine costs are given by the cost of labor teams and machines, plus $2,000 per engine for raw materials. Your plant has a fixed installation of 10 assembly machines as part of its design.a. What is the cost function for your plant — namely, how much would it cost to produce Qengines? What are average and marginal costs for producing Q engines? How do average costs vary with output?K is fixed at 10. The short-run production function then becomes Q = 40 L. This implies that for any level of output Q, the number of labor teams hired will be L = Q / 40. The total cost function is thusgiven by the sum of the costs of capital, labor, and raw materials:TC(Q) = rK + wL + 2000Q = (12,000)(10) + (3,000)(Q/40) + 2,000 Q= 120,000 + 2,075QThe average cost function is then given by:AC(Q) = TC(Q)/Q = 120,000/Q + 2,075and the marginal cost function is given by:∂ TC(Q) / ∂ Q = 2,075Marginal costs are constant and average costs will decrease as quantity increases (due to the fixed cost of capital).b. How many teams are required to producing 80 engines? What is the average cost perengine?To produce Q = 80 engines we need L = Q/40 labor teams or L = 2. Average costs are given byAC(Q) = 120,000/Q + 2,075or AC = 3575 c. You are asked to make recommendations for the design of a new production facility. Whatwould you suggest? In particular, what capital/labor (K/L) ratio should the new plant accommodate? If lower average cost were your only criterion, should you suggest that the new plant have more production capacity or less production capacity that the plant you currently manage?We no longer assume that K is fixed at 10. We need to find the combination of K and L which minimizes costs at any level of output Q. The cost-minimization rule is given byMP r =MP w .KLTo find the marginal product of capital, observe that increasing K by 1 unit increases Q by 4L, so MP K = 4L. Similarly, observe that increasing L by 1 unit increases Q by 4K, so MP L = 4K. (Mathematically, MP K = ∆Q /∆K = 4L and MP L = ∆Q /∆L = 4K.) Using these formulas in the cost-minimization rule, we obtain:4L/r = 4K/w or K / L = w / r = 3,000 / 12,000 = 1/4The new plant should accommodate a capital to labor ratio of 1 to 4.The firm’s capital -labor ratio is currently 10/2 or 5. To reduce average cost, the firm should either use more labor and less capital to produce the same output or it should hire more labor and increase output.*10. A computer company’s cost function, which relates its average cost of product ion AC to its cumulative output in thousands of computers CQ and its plant size in terms of thousands of computers produced per year Q, within the production range of 10,000 to 50,000 computers is given byAC = 10 - 0.1CQ + 0.3Q.a. Is there a learning curve effect?The learning curve describes the relationship between the cumulative output and the inputsrequired to produce a unit of output. Average cost measures the input requirements per unit ofoutput. Learning curve effects exist if average cost falls with increases in cumulative output.Here, average cost decreases as cumulative output, CQ, increases. Therefore, there are learningcurve effects.b. Are there increasing or decreasing returns to scale?To measure scale economies, calculate the elasticity of total cost, TC, with respect to output, Q:ETCTCQQTCTCQMCACC ===∆∆∆∆.If this elasticity is greater (less) than one, then there are decreasing (increasing) returns to scale, because total costs are rising faster (slower) than output. From average cost we can calculate total and marginal cost:TC = Q(AC) = 10Q - (0.1)(CQ)(Q) + 0.3Q2, thereforeMCdTCdQCQ Q ==-+100106...Because marginal cost is greater than average cost (because 0.6Q > 0.3Q), the elasticity, EC, is greater than one; there are decreasing returns to scale. The production process exhibits a learningeffect and decreasing returns to scale.c. During its existence, the firm has produced a total of 40,000 computers and is producing 10,000computers this year. Next year it plans to increase its production to 12,000 computers. Will its average cost of production increase or decrease? Explain.First, calculate average cost this year:AC1= 10 - 0.1CQ + 0.3Q = 10 - (0.1)(40) + (0.3)(10) = 9.Second, calculate the average cost next year:AC2= 10 - (0.1)(50) + (0.3)(12) = 8.6.(Note: Cumulative output has increased from 40,000 to 50,000.) The average cost will decreasebecause of the learning effect.11. The short-run cost function of a company is given by the equation C = 190 + 53Q, where C is the total cost and Q is the total quantity of output, both measured in tens of thousands.a. What is the company’s fixed cost?When Q = 0, C = 190 (or $1,900,000). Therefore, fixed cost is equal to 190 (or $1,900,000).b. If the company produced 100,000 units of goods, what is its average variable cost?With 100,000 units, Q= 10. Variable cost is 53Q= (53)(10) = 530 (or $5,300,000). Averagevariable cost is TVCQ==$530$53.10c. What is its marginal cost per unit produced?With constant average variable cost, marginal cost is equal to average variable cost, $53.d. What is its average fixed cost?At Q = 10, average fixed cost is TFCQ==$190$1910.e. Suppose the company borrows money and expands its factory. Its fixed cost rises by $50,000,but its variable cost falls to $45,000 per 10,000 units. The cost of interest (I) also enters into the equation. Each one-point increase in the interest rate raises costs by $30,000. Write the new cost equation.Fixed cost changes from 190 to 195. Variable cost decreases from 53 to 45. Fixed cost alsoincludes interest charges: 3I . The cost equation isC = 195 + 45Q + 3I .*12. Suppose the long-run total cost function for an industry is given by the cubic equation TC = a + bQ + cQ 2 + dQ 3. Show (using calculus) that this total cost function is consistent with a U-shaped average cost curve for at least some values of a, b, c, d.To show that the cubic cost equation implies a U -shaped average cost curve, we use algebra,calculus, and economic reasoning to place sign restrictions on the parameters of the equation.These techniques are illustrated by the example below.First, if output is equal to zero, then TC = a , where a represents fixed costs. In the short run,fixed costs are positive, a > 0, but in the long run, where all inputs are variable a = 0. Therefore,we restrict a to be zero.Next, we know that average cost must be positive. Dividing TC by Q:AC = b + cQ + dQ 2.This equation is simply a quadratic function. When graphed, it has two basic shapes: a U shapeand a hill shape. We want the U shape, i.e., a curve with a minimum (minimum average cost),rather than a hill shape with a maximum.To the left of the minimum, the slope should be negative (downward sloping). At the minimum,the slope should be zero, and to the right of the minimum the slope should be positive (upwardsloping). The first derivative of the average cost curve with respect to Q must be equal to zero atthe minimum. For a U -shaped AC curve, the second derivative of the average cost curve must bepositive.The first derivative is c + 2dQ ; the second derivative is 2d . If the second derivative is to bepositive, then d > 0. If the first derivative is equal to zero, then solving for c as a function of Qand d yields: c = -2dQ . If d and Q are both positive, then c must be negative: c < 0.To restrict b , we know that at its minimum, average cost must be positive. The minimum occurswhen c + 2dQ = 0. We solve for Q as a function of c and d : Q c=->0. Next, substitutingthis value for Q into our expression for average cost, and simplifying the equation:2222⎪⎪⎭⎫ ⎝⎛-⎪⎪⎭⎫ ⎝⎛-++=++=d c d c d c b dQ cQ b AC , orAC b b b c d cd cd c d c d =-=-+=->+2222223362660. implying b c d >26. Because c 2and d > 0, b must be positive.In summary, for U -shaped long-run average cost curves, a must be zero, b and d must be positive, cmust be negative, and 4db > c 2. However, the conditions do not insure that marginal cost is positive.To insure that marginal cost has a U shape and that its minimum is positive, using the sameprocedure, i.e., solving for Q at minimum marginal cost -c d /,3 and substituting into theexpression for marginal cost b + 2cQ + 3dQ 2, we find that c 2 must be less than 3bd . Notice thatparameter values that satisfy this condition also satisfy 4db > c 2, but not the reverse.where a, b, and c are positive. Is this total cost function consistent with the presence of economies or diseconomies of scale? With economies or diseconomies of scope?There are two types of scale economies to consider: multiproduct economies of scale and product-specific returns to scale. From Section 7.5 we know that multiproduct economies of scalefor the two-product case, S H,S , are()()()()()S H S H MC S MC H S H TC S +=, , where MC H is the marginal cost of producing hardware and MC S is the marginal cost of producingsoftware. The product-specific returns to scale are:()()()()H H MC H S TC S H TC S ,0 , -= and ()()()()S S MC S H TC S H TC S 0, , -= where TC (0,S ) implies no hardware production and TC (H ,0) implies no software production. Weknow that the marginal cost of an input is the slope of the total cost with respect to that input.Since()(),S cH b aH bS H cS a TC -+=+-=we have MC H = a - cS and MC S = b - cH .Substituting these expressions into our formulas for S H,S , S H , and S S :()()cH b S cS a H cHS bS aH S S H -+--+=, or S aH bS cHS H S ,=+-+->1, because cHS > 0. Also, ()()cS a H bS cHS bS aH S H ---+=, or()()()()1=--=--=cS a cS a cS a H cHS aH S H and similarly ()().1=---+=cH b S aH cHS bS aH S S There are multiproduct economies of scale, S H,S > 1, but constant product-specific returns to scale,S H = S C = 1.Economies of scope exist if S C > 0, where (from equation (7.8) in the text):()()()()S H TC S H TC S TC H TC S c , , ,0 0, -+=, or, ()()S H TC cHS bS aH bS aH S c , -+-+=, or ().0, >=S H TC cHS S c Because cHS and TC are both positive, there are economies of scope.CHAPTER 8PROFIT MAXIMIZATION AND COMPETITIVE SUPPLYAs the title implies, this chapter covers two interrelated topics: a consideration of the behavioral incentives of the profit-maximizing firm and an examination of the interaction of these firms in a competitive market. The chapter begins with a discussion of whether firms maximize profits and ends with a discussion of the criteria for a competitive market, including an introduction to contestable markets. Exercises (1), (2), and (4) rely on data discussed in the text, while Exercises (3), (6), and (7) focus on the determination of the firm’s profit -maximizing quantity. Exercises (5), (8), and (9) consider the influence of taxes on firms’ output in a competitive market.S ections 8.2 through 8.4 derive the firm’s supply curve. Although total revenue is easily understood, you will need to show why average revenue may be represented by the demand curve. Demand and average revenue will be used interchangeably in Chapters 10 and 11. When presented with a problem involving the derivation of marginal revenue, some students will substitute Q , instead of P , in the expression for total revenue. This leads to revenue as a function of price. Stress that when they are given a demand curve in these applications they should first solve for price as a function of quantity. The origin of this confusion could lie in the popular notion that the firm determines the profit-maximizing price instead of the profit-maximizing quantity. Emphasize the importance of quantity, for example, when discussing why deviations from the profit-maximizing quantity lead to a decrease in profit (see Figure 8.3). Using the solutions to the exercises, emphasize that, for a linear demand curve, the slope of the marginal revenue curve is twice the slope of the demand curve.Other sources of confusion arise during analysis of firms’ supply curves. Stress that, as a primary rule, the firm should choose a quantity such that marginal revenue is equal to marginal cost. In this chapter, we can simplify this rule: for a firm facing a perfectly elastic demand curve, price is equal to marginal revenue. Stress that the rule for the competitive firm is a special case. Although some students will understand references to second-order conditions, expect to be asked why q 0 in Figure 8.3 is not profit maximizing, although MR = MC . Two additional points warrant careful explanation: 1) why the firm would remain in business if the firm sustains a loss in the short run, and 2) that maximizing profit is the same as minimizing loss.Although the summation of firm supply curves into a market supply curve is easy, the analysis of long-run competitive equilibrium is difficult. Show that long-run equilibrium relies on profit maximization by firms. Accompanying the rule that price must be greater than average variable cost in the short run, there is the assumption of free entry and exit. This leads to the statement that price must equal long-run average cost, LAC, as no firm may make an economic profit. The rule that price must equal long-run marginal cost, LMC , is the second equilibrium condition. Therefore, because LAC = LMC at minimum LAC , price is equal to minimum LAC in the long-run equilibrium. This result will be reconsidered in Chapter 12 in the discussion of equilibrium for a monopolistically competitive firm. When discussing the attainment of equilibrium in constant, increasing, and。
(中文版)平狄克《微观经济学》全部课后答案
(中文版)平狄克《微观经济学》全部课后答案第一章复习题1．市场是通过相互作用决定一种或一系列产品价格的买卖双方的集合，因此可以把市场看作决定价格的场所。
行业是出售相同的或紧密相关的产品的厂商的集合，一个市场可以包括许多行业。
2．评价一个理论有两个步骤：首先，需要检验这个理论假设的合理性；第二，把该理论的预测和事实相比较以此来验证它。
如果一个理论无法被检验的话，它将不会被接受。
因此，它对我们理解现实情况没有任何帮助。
3．实证分析解释“是什么”的问题，而规范分析解释的是“应该是什么”的问题。
对供给的限制将改变市场的均衡。
A中包括两种分析，批评这是一种“失败的政策”——是规范分析，批评其破坏了市场的竞争性——是实证分析。
B向我们说明在燃油的配给制下总社会福利的被损坏——是实证分析。
4．由于两个市场在空间上是分离的，商品在两地间的运输是套利实现的条件。
如果运输成本为零，则可以在Oklahoma购买汽油，到New Jersey出售，赚取差价；如果这个差价无法弥补运输成本则不存在套利机会。
5．商品和服务的数量与价格由供求关系决定。
鸡蛋的实际价格从1970年至1985年的下降，一方面是由于人们健康意识的提高而导致鸡蛋需求的减少，同时也因为生产成本的降低。
在这两种因素下，鸡蛋的价格下降了。
大学教育的实际价格的升高，是由于越来越多的人倾向于获得大学教育而导致需求提高，同时教育的成本也在升高。
在这两方面因素作用下，大学教育费用提高了。
6．日圆相对美圆来说，价值升高，升值前相比，兑换同样数量的日圆需要付出更多的美圆。
由汇率的变化引起购买力的变化，在日本市场出售的美国汽车，由于美圆贬值日圆升值，持有日圆的消费者将较以前支付较底的价格；而在美国市场出售的日本汽车，由于日圆升值美圆贬值，持有美圆的消费者将面对较以前提高的价格。
4.长期弹性和短期弹性区别在于消费者对价格变化的反映速度以及可获得的替代品。
对纸巾这样的非耐用品，价格上升，消费者在短期内的反映很小。
平狄克微观经济学答案——第6章生产
第六章生产第六章是三章有关供给理论内容中的第一部分。
复习或总结学过的需求理论对总体观察竞争性供给理论是有帮助的。
复习有助于找出需求理论和供给理论的相似之处。
学生们通常都认为供给理论比较容易掌握，因为它们不是很抽象，而且对内容比较熟悉。
学习它可以有助于帮助学生在复习的时候更好的理解需求理论。
在本章中，重点要多花时间和精力掌握一些概念，因为它们是下两章的基础。
生产函数的内容并不难，但是有时候数学和图表表达式会引起疑惑。
多做例题会有所帮助的。
在做生产函数坐标图时，纵轴为产量，横轴为一种生产要素投入，表示生产函数是生产规划的范围，即无论投入量在任何水平的最高产量。
技术效率也在供给理论中加以了讨论。
在任何时间你都可以引入讨论提高生产效率的重要性并通过讨论得出内容。
课本中例1和例2都适合做讨论。
由生产函数的坐标图很自然的展开对边际产量和报酬递减的讨论。
强调报酬递减存在是因为一些生产要素已经被定义为固定不变，而且报酬递减并不代表报酬为负的。
如果你还没有讨论边际效用，那么是时候让学生知道平均和边际的不同了。
例如引导学生先从对考试的平均和边际成绩之间的关系来进入讨论。
如果他们上学期期中成绩高于平均成绩的话，这会提高他们的平均水平。
虽然等产量线在本章一开始就已给出定义，但是却是在本章的后面部分才用以分析。
在进行对等产量线讨论的过程中可以借助学生对无差异曲线的理解。
]并指出，等产量线是生产函数三维空间的二维表示。
本章最后部分的重点是边际技术替代率与规模报酬。
做尽可能多具体的例题用来帮助解释这两个重要的内容。
例6.3和6.4有助于加强理MRTS和规模报酬。
复习题1、什么是生产函数？短期生产函数和长期生产函数有何区别？生产函数代表企业的投入转换成为产出。
我们关注的是厂商的产出，以及生产要素的在一个生产周期内的总投入，例如：劳动力、资本以及原材料。
短期内一个或多个生产要素不会发生变化，随着时间的推移，厂商变有机会对投入的要素进行调整。
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第一章复习题1．市场是通过相互作用决定一种或一系列产品价格的买卖双方的集合，因此可以把市场看作决定价格的场所。
行业是出售相同的或紧密相关的产品的厂商的集合，一个市场可以包括许多行业。
2．评价一个理论有两个步骤：首先，需要检验这个理论假设的合理性；第二，把该理论的预测和事实相比较以此来验证它。
如果一个理论无法被检验的话，它将不会被接受。
因此，它对我们理解现实情况没有任何帮助。
3．实证分析解释“是什么”的问题，而规范分析解释的是“应该是什么”的问题。
对供给的限制将改变市场的均衡。
A中包括两种分析，批评这是一种“失败的政策”——是规范分析，批评其破坏了市场的竞争性——是实证分析。
B向我们说明在燃油的配给制下总社会福利的被损坏——是实证分析。
4．由于两个市场在空间上是分离的，商品在两地间的运输是套利实现的条件。
如果运输成本为零，则可以在Oklahoma购买汽油，到New Jersey出售，赚取差价；如果这个差价无法弥补运输成本则不存在套利机会。
5．商品和服务的数量与价格由供求关系决定。
鸡蛋的实际价格从1970年至1985年的下降，一方面是由于人们健康意识的提高而导致鸡蛋需求的减少，同时也因为生产成本的降低。
在这两种因素下，鸡蛋的价格下降了。
大学教育的实际价格的升高，是由于越来越多的人倾向于获得大学教育而导致需求提高，同时教育的成本也在升高。
在这两方面因素作用下，大学教育费用提高了。
6．日圆相对美圆来说，价值升高，升值前相比，兑换同样数量的日圆需要付出更多的美圆。
由汇率的变化引起购买力的变化，在日本市场出售的美国汽车，由于美圆贬值日圆升值，持有日圆的消费者将较以前支付较底的价格；而在美国市场出售的日本汽车，由于日圆升值美圆贬值，持有美圆的消费者将面对较以前提高的价格。
4.长期弹性和短期弹性区别在于消费者对价格变化的反映速度以及可获得的替代品。
对纸巾这样的非耐用品，价格上升，消费者在短期内的反映很小。
但在长期，对纸巾的需求将会变得富有弹性。
对于象电视机这样的耐用消费品，在短期内，价格的变动可能会引起需求的剧烈变化，价格的上升可能会使消费者推迟购买。
因此耐用品的需求在长期是富有弹性的。
5. 供给价格弹性是供给量变动的百分比和价格变动百分比的比值。
价格上升将引起供给的增加。
有些厂商在短期内，由于生产能力的限制无法迅速增加产量。
这样，在短期内，供给是缺乏弹性的。
然而在长期情况下，厂商可以调整生产规模，因而，从长期来看，供给是富有弹性的。
6. 如果商品价格被定在市场出清水平以下，厂商愿意提供的产量则低于消费者希望购买的数量。
短缺的程度则取决于供求的相对弹性。
供求均富有弹性情况下的缺口要大于双方缺乏弹性时的情况。
消费者无法在价格管制的情况下购买到他想购买到的数量。
他将去购买替代品，这样，替a.消费者将增加苹果需求，导致需求曲线外移动。
均衡价格和销售量都将增加。
b.由于橙子具有替代性，苹果的需求曲线将外移，均衡价格和销售量都将增加。
c.产量的下降将导致供给曲线向内移动，均衡价格上升，销售量下降。
d.苹果采摘着的增加将使苹果生产成本下降，供给增加，均衡价格下降，销售量上升。
e.供给曲线将外移，均衡价格下降，销售量上升。
练习题1.a.EQQPPPQQP DDDDD ==∆∆∆∆.P = 80， E d=–0.4 P = 100, E d=–0.56 b.EQQPPPQQP SSSSS ==∆∆∆∆.P = 80, E s=0.5.P = 100, E s=0.56c.均衡价格和数量为$100 ，18 million.d.价格定在80$，需求为20 million.，供给为16 million.，相差4 million.2.Q= 1,800 + 240PSQ= 2,580 - 194P.DQ= (2,580 - 194P) + 200 = 2,780 - 194PD1,800 + 240P = 2,780 - 194P, or434P = 980, or P* = $2.26 per bushel.Q= 1,800 + (240)(2.26) = 2,342SQ= 2,780 - (194)(2.26) = 2,342.D3.a.100 - 5P = 50 + 5P, P = $500.Q= 100 - (5)(5) = 75DQ= 50 + (5)(5) = 75.S租金在500美金时，750,000公寓可以被租掉。
当租金被控制在100美金时，供给量将达到550,000 (Q= 50 + (5)(100) = 550)，S比管制前减少了200,000。
假设每个公寓可容纳一个三口之家，将有600,000离开城市。
Figure 2.3b.当租金达到900美金时，公寓的供给为50 + 5(9) = 95，or 950,000这将超过均衡水平200,000。
因此(0.5)(200,000) = 100,000 个公寓被新建。
但是需求仅仅为550,000。
4. a.由总需求 Q = 3,550 - 266P , 国内需求, Q d = 1,000 - 46P , ,得到出口需求Q e = 2,550 - 220P . 均衡价格：3,550 - 266P - 1,800 + 240P , orP = $3.46.需求减少40％，因此总需求Q D = Q d + 0.6Q e = 1,000 - 46P + (0.6)(2,550 - 220P ) = 2,530 - 178P .均衡价格1,800 + 240P = 2,530 - 178P , orP = $1.75,在这一价格，市场出清量为2,219 million bushels ，总收益从$9.1 billion 降至 $3.9 billion.这将令大部分农民痛苦。
b.3美金的价格下市场并不在均衡状态，Demand = 1000 - 46(3) = 862. Supply = 1800 + 240(3) = 2,520, 超额供给 2,520 - 862 = 1,658.政府必须购买这个多余产量来支持价格，花费$3(1.66 million) = $5.0 billion 每年。
5. a.Q D = a - bP . E bP Q D =-F H G I KJ **. E D= -0.4 (长期价格弹性), P* = 0.75 (均衡价格), Q* = 7.5 (均衡产量).-=-F H I K 0407575...b, or b = 4.7.5 = a - (4)(0.75), or a = 10.5.Q D = 10.5 - 4P .b.)需求下降20％:'Q D=-=-0810548432....a f a fP P .8.4 - 3.2P = -4.5 + 16P , orP = 0.672.6. a.D = 24.08 - 0.06P S C = 11.74 + 0.07P .在没有OPEC 组织下的供给S c = Q * = 13.E S = 0.10 ， P * = $18, E S = d (P */Q *) ， d = 0.07.代入 d , S c , ， P , c = 11.74 and S c = 11.74 + 0.07P .同样的, 因为 Q D = 23, E D = -b (P */Q *) = -0.05, b = 0.06. 代入 b , Q D = 23, ， P = 1823 = a - 0.06(18), a = 24.08. 因此 Q D = 24.08 - 0.06P .b.D = 32.18 - 0.51P S C = 7.78 + 0.29P .如上, E S = 0.4 ， E D = -0.4: E S = d (P */Q *) ， E D = -b(P*/Q*), 0.4 = d (18/13) and -0.4 = -b (18/23).所以 d = 0.29 ， b = 0.51.S c = c + dP ， Q D = a - bP ,13 = c + (0.29)(18) ， 23 = a - (0.51)(18).So c = 7.78 ， a = 32.18.c.减产60亿桶后：S c = 4 + S c = 11.74 + 4 + 0.07P = 15.74 + 0.07P ，S = 4 + S c = 11.78 + 0.29P .15.74 + 0.07P = 24.08 - 0.06P ,短期中，P = $64.15;11.78 + 0.29P = 32.18 - 0.51P ,长期中，P = $24.297. a.供给: Q = 14 + 2P G + 0.25P O 需求: Q = -5P G + 3.75P O需求交叉弹性为：E Q P P Q GO GOGG=F HG I K J F HG I K J ∆∆. 设需求函数为：Q G = a - bP G + eP O(收入为常量), 则∆∆Q PG OF HG I K J = e . 将它代入交叉弹性公式, Ee P Q POOG=F HG I K J **, P O*and Q G * 是均衡价格和产量. 我们知道 P O * = $8 ， Q G* = 20 百万立方英尺(Tcf). 解得 e ,15820.=F H G I KJ e, e = 3.75.同样得, 供给方程可表示为:Q G = c + dP G + gP O ,交叉价格弹性为 g P Q O G**F HG I K J , e= 0.1. ⎪⎭⎫⎝⎛=2081.0g , g = 0.25.E S = 0.2, P* = 2, Q* = 20. 因此⎪⎭⎫⎝⎛=2022.0d , d = 2.同样, E D = -0.5, 所以⎪⎭⎫⎝⎛=-2025.0b , b = -5.将d, g, b , ， e 代入供给，需求方程，解得：20 = c + (2)(2) + (0.25)(8), c = 14, 20 = a - (5)(2) + (3.75)(8), a = 0.如果油价为$8.00，意味着天然气价格为$2.00。
将油价代入供求方程，得到天然气价格14 + 2P G + (0.25)(8) = -5P G + (3.75)(8), 7P G = 14, orP G = $2.00.b.需求: Q D = (-5)(1.50) + (3.75)(8) = 22.5, 供给: Q S = 14 + (2)(1.5) + (0.25)(8) = 19.在这种情况下将出现超额需求3.5 Tcf.c.需求: Q D = -5P G + (3.75)(16) = 60 - 5P G , 供给: Q S = 14 + 2P G + (0.25)(16) = 18 + 2P G .18 + 2P G = 60 - 5P G , ，P G = $6.第三章复习题1、偏好的可传递性是指：如果消费者在市场篮子A和B中更偏好A，在B和C中更偏好B，那么消费者A和C中更偏好A。