萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(不确定性和博弈论)【圣才出品】

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萨缪尔森经济学Economics第十八版 18th 课后概念、习题答案2

萨缪尔森经济学Economics第十八版 18th 课后概念、习题答案2

C H A P T E R 2 T h e S h i f t i n g B o u n d a r y B e t w e e nM a r k e t sa n d G o v e r n m e n tCHAPTER OVERVIEW AND TEACHING TIPSThis chapter introduces a series of fundamental ideas and concepts that define the essence of the economic problem. They are important because they form the foundation for the analysis of a market economy. The tools and methods that you present to students in this chapter will be carried throughout the text and developed in greater detail as you make your way through the course. Here is a great opportunity for you to give students a broad introduction to “the economic way of thinking.”The chapter begins with an introduction to markets. Because this text is grounded in market analysis, take the time to illustrate the basics concepts of upward-sloping supply, downward-sloping demand, and equilibrium. Later chapters will fill in important details.Section B broadens the students’ view of the economy from a partial equilibrium setting to a more general equilibri- um setting. This allows you to develop the important interactions between agents and markets. Roles for money and capital are established as well as the importance of property rights. All of these components of a market economy are important to its proper functioning.Section C introduces a role for government in an economy. Efficiency and equity are examined as well as macroe- conomic goals like growth and stability.LEARNING OBJECTIVES1. Describe what is meant by the term market and describe the process of achieving equilibrium in a market economy.2. Use your definition of market equilibrium to address three basic economic problems that confront all societies.3. Explain how the price system works as an invisible hand, allocating goods and services in a market economy.4. Understand the importance of specialization, the division of labor, money, factors of production and capital andproperty rights in the functioning of a modern economy.5. Use a circular-flow diagram to illustrate the relationships between agents and markets in a modern economy.6. Make a case for government intervention in a mixed market economy in order to promote efficiency, equity, andmacroeconomic growth and stability.SUGGESTED ANSWERS TO QUESTIONS IN THE TEXT1. In all of these cases, a combination of consumer choice and government directives or incentive plans determine theultimate allocation of resources.2. Auctions are not always practical, ration coupons hold prices artificially low, and first come first served leads tohigh opportunity costs of standing in line. A market “rations” goods to those consumers who can a fford them.3. There are lots of potential government failures. Some would argue that AFDC has been a failure; more children livein poverty in the United States today than in many other industralized countries. Would it be better to live with this market failure? We shall see.4. Pollution limitations: improving efficiency (public bad)Income supplements: equity (redistribution program)Phone regulation: efficiency (prices higher, output lower with monopoly)56 C HAPTER 2: T HE S HIFTING B OUNDARY B ETWEEN M ARKETS AND G OVERNMENT 5. Money goes in the opposite direction, i.e., from businesses to the suppliers of inputs and from households to thesuppliers of outputs. Money functions to make transactions easier and more efficient.6. Division and specialization of labor is obvious in a college or university. Faculty membersteach classes, staff members clean classrooms and deliver mail, and administrators manage budgets and raise funds for the institution. Overspecialization might leave some individuals unemployable if the demand for their type of labor decreases.7. There were arguments that slaves were property. Some argued that because slaves had to be housed and fed frombirth and trained from adolescence, they represented “human” capital—human elements of roundabout production.I am sure that you can find a lot to write about such a dehumanizing thought.8. Social security helps to promote equity in the distribution of income. National defense represents provision ofa public good. Unemployment insurance provides for stability through the business cycle. Interest on the publicdebt might promote stability by allowing government to use fiscal policy more effectively.Administration of justice often deals with imperfect competition and market failure. Pollution control battles a negative externality, while funding for basic science encourages a positive externality.9. Unlike a private good where you must reveal your preferences to receive the good, public goods are provided by thegovernment and are paid for by taxes collected by the government. It is important that the one who is paying for the good have a say in what is provided by the government.a. The best way to voice your concern about defense spending is at the ballot box.b. You can voice your displeasure at the ballot box or move to a jurisdiction where the tax is not being collected.c. Take alternative means of travel to Miami or not travel to Miami.DISCUSSION QUESTIONS1. What is meant by a “mixed economy?” Is it socialist? Communist?2. It has been said that prices serve a rationing function and a guidepost function. What could this mean?3. Use a market diagram to show how prices coordinate the behavior of buyers and sellers. What if buyers wantto purchase more units of a particular good than sellers want to provide? How will the price system provideincentivesin this situation?4. The how, what, and for whom questions are solved differently in different economic systems. Consider each ofthe following and explain how the three big questions of economic organization are solved (a) within your family,(b) within your college or university, and (c) in the agriculture industry.5. What considerations do you think have caused leaders in Eastern Europe to lessen their hostility toward the valueof the pricing system? What about the people? If market economies work better than other types of economic rationing systems, why is it so difficult for countries like Russia and Poland to chart a new economic course?6. Why do you suppose that history has never seen a period of complete laissez-faire? Do youthink nineteenth century America came reasonably close? What would your Utopia look like?7. “Losses are as important as profits in a pricing system.” Why? What function do losses serve?8. Identify a few economic areas in which the government is currently active. Are these activities directedprimarily toward correcting problems of equity, efficiency, or stability? Are they working? Discuss positive and negative effects of government intervention in the economy.9. The social security system was devised to help Americans during their retirement years. It has grown beyondthat objective. What are the current objectives of the system, and are there side effects that add to or subtract from its ability to meet those objectives?10. Why is the decision whether to consume today or tomorrow so important to society? Who makes this decision inthe United States? In Cuba?11. “A socialist nation and a capitalist nation do not differ in the fundamental economic problems that they face;they differ in the ways they go about solving those problems.” Do you agree? Why or why not? Do they also differ in what they consider to be desirable solutions?12. Do you think society could organize 200 million people on the principles of the kibbutz or cooperative? Why orwhy not?13. “Th e need of U.S. manufacturers to spend large sums on advertising to stimulate artificial wantsindicates that economic scarcity will soon lose its relevance.” Is this true, and if not true no w, is it likely to become so?14. Who loses, or stands to lose, when trade opens? Do they always lose? Can short-term losses turn into long-term gains?C HAPTER 2: T HE S HIFTING B OUNDARY B ETWEEN M ARKETS AND G OVERNMENT 715. What types of stabilization policies can you think of? Are they consistent with the objectives of equity andefficiency?16. Equity and efficiency can run counter to each other. Why?17. Do markets always do a good job of distributing resources to people who need them most? To people who wantthem most? Explain.ESSAY QUESTIONS1. Sketch a diagram to show how markets and prices link households and businesses to solve the three economic prob-lems. Explain the direction of money flows and the accompanying flows of goods and factor inputs.2. Prices in a market system have sometimes been described as fulfilling a “rationing” function.a. In what sense do prices “ration?” Why is rationing needed in an economic system as productive as ours?b. In the market for energy, what are the factors determining to whom the world’s supply of oil is distributed?c. Suppose a shortage of wheat exists. How does the price system react to bring about anincrease in wheat production?3. Indicate the manner in which the market system provides a solution to the for whom question in a free enterpriseeconomy. In the present American economy, what other factors are important?4. “The U.S. economic system is mixed in at least two senses.” Elaborate on this statement.5. List and discuss (a) the various factors inherent in our economy that make perfect competitionan unrealistic description of our economic system; (b) the factors responsible for the existence of monopoly elements in our society.6. “The bulk of all economic activity is directed toward the future.” What would be the significance of this for oursociety? Is it true?7. Government in a mixed society can (a) purchase goods and services, (b) produce goods and services, (c) transferincome from one group of people to another, (d) tax its citizens, and (e) borrow and/or lend money. Pick examples of each and discuss how equity, efficiency, and stabilization objectives are met in your examples.8. In The Zero Sum Society, Lester Thurow speculates on how economic interaction can take placewithout one person’s gain resulting in another’s loss. What do you think of that notion? How might it relate to globalization?9. Contrast the use of barter and money in a modern mixed economy that uses many capital goods and involves muchspecialization and interdependence. Concentrate on the efficiency of transactions—the cost involved in conducting business.10. “Specialization gives rise to di fferences in skill; differences in skill give rise to s pecialization.” Can both statementsbe true? Would specialization be worthwhile if everyone were identical?11. In what sense do specialization and division of labor depend on the size of the market? Does this help explainthe phenomenon of continuing economic growth?12. Specialization is not entirely problem-free. Discuss some of the troublesome effects of specialization on workers,the workplace, and society as a whole.13. Country A can produce all goods more efficiently than Country B. The opportunity costs of production, however,are different. Can trade ever benefit Country A?14. Discuss the fundamental difference between Milton Friedman’s ideas about a market economy and John MaynardKeynes’ ideas about a market economy. What are their major points of disagreement?15. Discuss the problems associated with providing the service of a lighthouse to ships.。

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(供给和需求的应用)【圣才出品】

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(供给和需求的应用)【圣才出品】

第4章 供给和需求的应用4.1 复习笔记一、需求弹性和供给弹性1.需求的价格弹性(1)含义需求价格弹性是指需求量相对于价格变化作出的反应程度,即某商品价格下降或上升百分之一时所引起的对该商品需求量增加或减少的百分比。

(2)公式①需求弧弹性表示需求曲线上两点之间的弹性,其计算公式为:。

D D D Q P E P Q ∆=⋅∆②点弹性表示的是需求曲线上某一点的弹性,其计算公式为:。

d d D D DQ P E P Q =⋅③计算需求的弧弹性时,两点之间的变动率既可以以起点为基础,也可以以终点为基础,还可以以中点为基础。

也就是,弧弹性公式中(,)取起点、终点与中点的坐标P D Q 都成立。

一般地,以中点为基准计算弧弹性,其公式为:()()1212/2/2D Q PE Q Q P P ∆∆=÷++(3)类型①,称为完全无弹性,表明需求量为一常量,即需求量不随价格变化而变化,0D E =需求曲线和纵轴平行,其斜率为无穷大。

这是一种特例,如火葬费、自来水费等近似于无弹性,如图4-1所示。

图4-1 完全无弹性与完全弹性②,称为无穷大弹性或完全弹性,表明价格为一定的情况下,需求量无限大,D E =∞此时,需求曲线斜率为零。

这也是一种特例,如战争时期的常规军用物资及完全竞争条件下的商品可视为需求弹性无限大,如图4-1所示。

③,称为富有弹性,表明需求量的变动率快于价格的变动率,即需求量对价1D E <<∞格变化反应强烈,此时,需求曲线斜率为负。

这类商品称之为奢侈品,一般指高档消费品,如图4-2(a )所示。

④,称为单一弹性或单位弹性,表明需求量的变动率等于价格的变动率,即需1D E =求和价格以相同幅度变动,这是一种特例,如图4-2(b )所示。

⑤,称为缺乏弹性,表明需求量的变动率小于价格的变动率,即需求量变化01D E <<对价格变化反应缓和。

此时,需求曲线斜率为负。

这类商品为生活必需品,如图4-2(c )所示。

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(需求和消费者行为)【圣才出品】

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(需求和消费者行为)【圣才出品】

第5章需求和消费者行为5.1 复习笔记一、选择和效用理论1.消费者的选择在解释消费行为的过程中,经济学依赖于一个基本的前提假定,即人们倾向于选择他们认为最具价值的那些物品和服务。

也就是说,消费者运用有限的货币收入,通过有选择的购买行为以取得最大的效用。

消费者的选择由两个因素决定:(1)消费者的偏好;(2)消费者的收入水平和所购买商品或劳务的价格水平。

2.效用(1)效用的概念效用是消费者从消费某种物品或劳务中所得到的满足程度,是消费者的一种心理感受而不是物品的客观用途。

同一商品效用的大小因人、因时、因地而不同。

对效用的不同度量形成了两种效用理论,即基数效用论与序数效用论。

(2)基数效用论基数效用论产生于19世纪70年代,它认为效用的大小可以计量并且不同消费者的效用可以进行加总计算,因此可以用基数1、2、3等来表示效用,其计数单位就是效用单位。

基数效用论采用边际分析法分析消费者的均衡问题。

(3)序数效用论序数效用论产生于19世纪末、20世纪初,是对基数效用论的补充和完善,它认为效用作为一种心理现象无法计量,也不能加总求和,只能表示出满足程度的高低与顺序,因此,效用只能用序数(第一、第二、第三……)来表示。

序数效用论采用无差异曲线分析法分析消费者的均衡问题。

二、边际效用分析1.边际效用与总效用(1)边际效用的定义边际效用是消费者在一定时间内增加一单位商品的消费所得到的效用量的增量,其表达式为:()TU Q MU Q∆=∆其中,为消费者对商品的消费数量,为总效用函数。

当商品的增加量趋Q ()TU f Q =于无穷小,即时,边际效用也可以表示为:0Q ∆→()()d lim d Q TU Q TU Q MU Q Q ∆→∆==∆(2)边际效用与总效用的关系总效用是消费者在一定时期,从一定数量的商品和劳务的消费中所得到的总的满足。

边际效用是指每增加(减少)一个单位商品或劳务的消费量所引起的总效用的增(减)量。

萨缪尔森经济学Economics第十八版 18th 课后概念、习题答案5

萨缪尔森经济学Economics第十八版 18th 课后概念、习题答案5

C H A P T E R 5A P P E N D I XG e o m e t r i c a l A n a l y s i so f C o n s u m e r E q u i l i b r i u mAPPENDIX OVERVIEW AND TEACHING TIPSThis appendix is designed to explain how consumers can use their fixed incomes to create the most utility possible, given their own personal tastes and prices dictated by the market. It begins with the same styliz ed description of the consumer’s dilemma that your students have seen in the chapter, and it reaches the same results. In fact, only the method of description is different; the problem of maximizing satisfaction subject to a budget constraint is illustrated using a diagram.If your students are like mine, they will ask, “So, why bother?” To be sure, the graph will deal with the very simple case in which only two goods are involved. Y ou will need to argue that the model helps to describe consumer behavior in a simple case, and it can be used to untangle more difficult questions. The simple geometry will clarify the general nature of making choices over many goods in the face of scarcity. The content of the analysis is not confi ned to the two- good case that can be drawn on a piece of graph paper.It is important to impress upon your students that the geometric approach frees us from having to make the assump- tion that consumers’utility functions are cardinal. The geometry assumes, instead, that people can display their prefer- ences simply by ranking different possible combinations of goods. Constructing the geometry of consumer decision making requires only that consumers are able to express a preference between two or more alternatives; i.e., they are able to say which combination of goods they want. Students generally find this ordinal notion far easier to swallow thana theory that suggests that consumers are able to quantitatively evaluate consumption bundles.LEARNING OBJECTIVES1. Define an indifference curve and an indifference map.2. Explain why indifference curves may vary from one individual to the next.3. Show how it would be impossible for an indifference curve representing normal preferences to run in the southwest-to-northeast direction.4. Describe what is meant by a budget constraint.5. Explain how the budget constraint shifts when income changes or when one of the two prices changes. SUGGESTED ANSWERS TO QUESTIONS IN THE TEXT1. Indifference curves for complementary goods should be L-shaped. Indifference curves between perfect substitutesshould be downward-sloping and linear, with slope = -1.2. See diagram (top of page 24).DISCUSSION QUESTIONS1. Using an indifference map and a budget line, derive the law of downward-sloping demand.2. What is an indifference curve? Why is it convex to the origin? What is the significance of its slope at any point?2324 C HAPTER 5 A PPENDIX: G EOMETRICAL A NALYSIS OF C ONSUMER E Q UILIBRIUMFig ure5-1Will two indifference curves intersect? Why or why not?3. Using a set of indifference curves between food and clothing and a budget line, show the consumer’s new equilibri-um relative to her old equilibrium position when (a) her income increases, but both prices remain constant; (b) the price of food falls, but her income and other prices are fixed.4. The theory of consumer behavior may be applied to the choice between labor and leisure as wellas the choice among physical commodities. Each individual may choose between daily income and leisure (equal to 24 hours less the hours slept per day). Both income and leisure are positively valued. Derive the supply curve of labor forthe individual, using the indifference-curve analysis.ESSAY QUESTIONS1. Draw a budget constraint for an individual who has $400 to spend on sweaters and sweatshirts, when the price of asweater is $50 and the price of a sweatshirt is $30. If sweaters and sweatshirts are perfect substitutes, how does the consumer choose which to buy? Explain your diagram.2. Suppose the consumer in question 1 experiences a $100 decrease in her budget. How will this affect the budgetconstraint? Show in your diagram and explain.3. Suppose the consumer in question 1 notices that the price of a sweatshirt has increased to $50. How will this affectthe budget constraint? Show in your diagram and explain.4. Why do you need both an indifference map and a budget constraint to solve the consumer problem? What informa-tion do you get from the budget constraint that you do not have in the indifference map?5. Suppose you have an individual who loves jelly but who hates peanut butter. In fact, this consumer is allergic topeanut butter. Draw some indifference curves that represent these preferences over peanut butter and jelly.6. Suppose you have an individual who believes that Coke and Pepsi are perfect substitutes. That is, theconsumer gets exactly the same utility from consuming a can of Coke or a can of Pepsi. Draw some indifference curves that represent these preferences.7. Use an indifference map and a budget constraint to show why the tangency solution is preferred to any other pointon the budget constraint or under the budget constraint.。

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(含考研真题)(10-14章)【圣才出品】

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(含考研真题)(10-14章)【圣才出品】

第10章寡头和垄断竞争10.1复习笔记一、不完全竞争者的行为1.市场力量及其衡量市场力量表示单个企业或少数企业控制某一产业的价格和生产决策的程度。

市场力量最常用的衡量指标是一个产业的集中率。

其中,四企业集中率是指四家最大的厂商在某个产业的总产量(或发货量)中所占的百分比;同样,八企业集中率就是前八大厂商在某个产业总产量中所占的百分比。

在完全垄断的情况下,四家或八家企业的集中率都是100%,因为一家企业就生产了所有的产品,而对于完全竞争来说,这两种集中率都接近于零,因为即使是最大企业也只是行业中全部产出的一小部分。

许多经济学家认为,传统的集中率没有能够充分地衡量市场力量。

赫芬达尔—赫希曼指数(HHI)是一种更好的衡量那些占统治地位的企业在行业中的角色的方法。

该指数是将一个市场中所有参与者所占的市场份额的比率的平方进行加总而获得的。

完全竞争的HHI 接近零,而完全垄断的HHI则是10000。

2.不完全竞争的实质经济学家发现不完全竞争市场存在着三个主要的因素:成本、进入壁垒和企业策略互动。

首先,对一个企业来说,当最低平均成本所对应的产出水平占该产业总产量的相当大的比例时,只有少数几个企业可以获利并生存下来,结果就很可能形成寡头。

其次,当由于存在规模经济或政府限制而形成进入壁垒时,一个产业的竞争者的数量就会十分有限。

再次,当在某一市场上仅仅有少数几个企业时,它们必然会认识到它们之间的相互依赖性。

策略互动是寡头市场的一个新的特征,属博弈论研究领域。

当每个企业的经营战略取决于它的竞争对手的行为时,就会出现策略互动。

3.勾结寡头(1)勾结的含义一个市场不完全竞争的程度并不仅取决于企业的数量和规模,也取决于企业的行为。

当市场上企业为数不多时,它们就会注意竞争对手的行为和反应:它们可以在合作与不合作的行为之间做出选择。

当企业按照自己的计划行动,而没有公开地或暗中勾结其他企业时,它们就是以非合作方式共处,这会形成价格大战。

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(促进市场更富效率)【圣才出品】

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(促进市场更富效率)【圣才出品】

第17章促进市场更富效率17.1 复习笔记一、企业管制:理论与实践1.管制及其种类管制的基本内容是制定政府条例和设计市场激励机制,以控制厂商的价格、销售或生产等决策。

管制传统上可分为经济管制和社会管制两类。

经济管制是指对价格、市场进入和退出条件、服务标准等所进行的控制。

这种管制在自然垄断行业中很重要。

常见的例子包括公用设施管制(电话、电、天然气、水)以及其他的产业管制(运输、电台、电视台)。

社会管制是指用来保护环境以及劳工和消费者的健康和安全的管制。

社会管制的有关规定可用以矫正经济活动所引起的各种派生后果和外部性问题。

突出的例子有:净化空气、净化水源、确保核安全、解决臭氧层变薄和气候变化等全球环境问题。

2.管制的原因管制是对企业无节制的市场力量的一种限制。

政府管制具有三大公众利益理由:一是管制企业行为可以防止垄断或寡头垄断滥用市场力量;二是管制可以矫正信息的不完全;三是管制可以纠正诸如污染之类的负的外部性问题。

(1)抑制市场力量政府应该对企业数目太少的产业实行管制,削弱过强的市场力量,以激发强有力的竞争。

政府特别应该对自然垄断这种极端情况实施管制。

当一个产业的规模经济或范围经济如此之强有力,以至于只有一个厂商能较好地生存下去时,就会产生自然垄断。

自然垄断的一个重要例子是地方水资源分配。

取水、建立水资源分配系统、铺设管道向用户送水的成本是如此之高,以至于让多个企业建立各自的供水系统势必得不偿失,这就是自然垄断。

另一种自然垄断产生于那些具有范围经济的产业,即把大量不同的产品放在一起生产,比单独生产某一种势必要来得更有效率。

一个重要且有争议的例子是计算机软件业。

产生自然垄断的最后一个原因就是在网络化的产业中,整个系统的有效运行都需要标准化和一致性。

政府管制自然垄断是因为,自然垄断者相对于竞争者来说,享有极大的成本优势,而且面对的是缺乏价格弹性的需求,所以能大幅度地提高价格,获得巨额垄断利润,导致经济在很大程度上的无效率。

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(供给与需求的基本原理)【圣才出品】

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(供给与需求的基本原理)【圣才出品】

第3章供给与需求的基本原理3.1 复习笔记一、需求概述1.需求表与需求曲线(1)需求的概念需求是指在一定的条件下,消费者在一系列可能的价格水平下愿意而且能够购买的商品的数量与价格之间的对应关系。

它包含两层含义:消费者既有购买的欲望,又有支付该商品价格的购买能力。

需求表示了消费者在每个价格下消费商品数量的计划。

一般说来,随着商品价格的提高,消费者消费商品的数量减少。

根据定义,如果消费者对某种商品只有购买的欲望而没有购买的能力,就不能算作是需求。

需求必须是既有购买欲望又有购买能力的有效需求。

所有消费者对一种商品的需求构成该商品的市场需求,它是由一系列可能的价格水平下所有消费者的需求总量所决定的。

(2)需求表需求表是某商品的各种价格和相应的需求数量的数字序列表,把需求表里的数字序列用曲线形式表示出来就是需求曲线。

(3)需求曲线需求曲线是表示商品需求数量与价格之间函数关系的曲线,一般表示需求量的函数关系。

它表明,在其他情况不变时,一个特定群体(在特定情况下也可以指单个的个人)某一特定时期内在各种价格水平下所购买的某种商品的数量。

需求曲线图形以纵轴表示价格,横轴表示商品数量。

市场需求曲线可以通过将在每一价格水平下所有个人的需求量加总而得到。

2.需求法则(1)需求曲线向下倾斜规律需求法则也称为需求曲线向下倾斜规律,是指在其他条件不变的情况下,随着某种商品或劳务的价格上升(或下降),对该商品或劳务的需求量减少(或增加)的规律;也就是说,商品或劳务的价格与其需求量成反比。

需求法则是造成需求曲线斜率为负的原因。

大多数的一般商品都会满足上述需求法则,但现实生活中并非所有商品都会满足需求法则,例如:①吉芬商品,如马铃薯;②炫耀性物品,如钻石。

(2)需求曲线向下倾斜的原因①替代效应:指由商品的价格变动所引起的商品相对价格的变动,进而由商品的相对价格变动所引起的商品需求量的变动。

—种商品的价格下降将引起消费者用该种商品去替代那些价格未下降或上升的商品。

萨缪尔森经济学Economics第十八版 18th 课后概念、习题答案4

萨缪尔森经济学Economics第十八版 18th 课后概念、习题答案4

C H A P T E R 4A p p l i c a t i o n s o fS u p p l y a n d D e m a n dCHAPTER OVERVIEW AND TEACHING TIPSIn Chapter 3 you explained the laws of supply and demand, and you familiarized students with the effects of changes in supply and demand. This leads naturally to the related question, “By how much?” How large are the responses to changes in the market, and on what does this responsiveness depend? This chapter introduces students to the concept of elasticity and exposes them to two types of elasticities: price elasticity of demand and price elasticity of supply. These concepts are difficult for students, particularly for those who have math anxiety. Emphasize the importance of percent- age changes in the numerator and denominator of the elasticity equations, and distinguish between price elasticity of demand and the slope of the demand curve. Do not hesitate to spend class time working through examples that illustratethe relationships between the price elasticity of demand and supply, and the demand and supply curves.The final section of the chapter provides students with the opportunity to apply market analysis and elasticity concepts in the arena of public policy-making. Distinguish carefully between the party who writes the check to the gov- ernment for a tax and the party who bears the economic burden of taxation. Just because taxes are often “paid” to the government by sellers does not mean that the sellers actually experience reduced incomes when new taxes are imposed. Price ceilings and price floors describe another type of government intervention into the operation of markets.LEARNING OBJECTIVES1. Define the term price elasticity of demand.2. Discuss the factors that determine whether price elasticity of demand is elastic, unitary-elastic, orinelastic, and compare consumer behavior in the short run and the long run. Describe elastic and inelastic regions that exist along any demand curve.3. Calculate price elasticity of demand using a method of averages, ant interpret your result.4. Explain, using diagrams, the relationship between total revenue and price elasticity of demand.5. Define the term price elasticity of supply.6. Discuss the factors that determine whether price elasticity of supply is elastic, unitary-elastic, orinelastic, and compare consumer behavior in the short run and the long run.7. Calculate price elasticity of supply using a method of averages, and interpret your result.8. Apply supply, demand, and elasticity concepts to the following situations and markets: (a) agriculture markets, (b)gasoline taxes, (c) minimum wages, and (d) energy price controls.SUGGESTED ANSWERS TO QUESTIONS IN THE TEXT1. A good harvest shifts a fairly inelastic supply curve to the right. Equilibrium moves down alonga relatively inelastic demand curve to support a (much) lower price, and hence lower farm revenues.2. More price elastic: perfume and ice cream because they are closer to luxuries than necessities; chocolate icecream and automobiles because there are more substitutes for these goods than there are for ice cream and automobile tires, respectively.3. Demand would be inelastic, with E D = .5.4. Assume that demand and supply both show some price elasticity.a. Output and price up along supply curve (demand-curve shift), assuming apartments are normal goods.b. Output down and price (paid by renters) up along demand curve (supply shift).c. If this price is below equilibrium (which makes sense if the policy is to have an impact), this is a price ceiling,established to protect buyers. A shortage of apartments will result, with quantity demanded greater than quantity supplied.1516 C HAPTER 4: A PPLICATIONS OF S UPPLY AND D EMAND d. Output up and price down along demand curve (supply shift).e. Output down and price up along demand curve (supply shift).5. According to the text, a 10% increase in the minimum wage would decrease employment of teenagers between 1and 3 percent. The impact on the adult population is even smaller. Thus, income for teenagers and adults would rise. Thus, if I had to make a decision on increasing the minimum wage, and if raising wages for low-wage workers were important to me, I would certainly vote to increase the minimum.6. Minimum wages can increase the quantity of labor supplied and decrease the quantity of labor demanded. Abind- ing minimum wage therefore creates a surplus of labor. Price ceilings can have the opposite effect. A legal maximum interest rate can lead to a shortage of loanable funds, with lenders willing to supply fewer funds than demanders would like to borrow. See Figure 4-1 for an illustration of the impact of a minimum wage on the marketfor unskilled workers when the demand is relatively elastic for those workers. Area B is lost due to the minimumwage, area A is gained, resulting in smaller earnings overall.Figure 4-1 7. The $2000 tariff on imported automobiles will act like a tax in that market, shifting the supply curve to the left by the amount of the tariff and resulting in lower quantities exchanged at a higher price. This will encourage con- sumers to substitute into autos produced by domestic firms, increasing the demand for those cars. The price and quantity exchanged of autos produced by domestic firms will rise, resulting in greater revenues for domestic automakers. 8. a. Supply down by 5 percent with elasticity of 0.05 means that price must increase by 100 percent. b. Elasticity is a ratio of percentages; it is thus unitless. c. Supply down by 50 percent means that price must increase by 100 percent to keep the price elasticity equal to 0.5. Crime should increase if addicts steal to feed their habits. A successful rehab program would shift demand in; quantity would fall by 50 percent and price would stay the same (the shifts would match). d. This policy would shift the supply of pork to the left, raising market prices. If, as argued in this chapter, the demand for agriculture products is inelastic, higher prices will result in higher farm incomes. e. The income rectangle is larger after the minimum wage is increased. This tells us that the price elasticity of demand for unskilled workers if very low; changes in the wage have little impact on the quantity of these laborers demanded. 9. a. See diagram. Figure 4-2C HAPTER 4: A PPLICATIONS OF S UPPLY AND D EMAND 17b. The vacancy rate will fall, there will be a shortage of apartments at the ceiling price.Figure 4-3c. The government might subsidize landlords in order to provide higher compensation for apartments.d. Rent controls limit the amount of compensation that landlords can receive for their property. This limits theirwillingness to maintain property, thus giving rise to the concerns of the European critic.10. The demand curve is given by P = 6.56 -.08Q, the supply curve is perfectly elastic at a price of $2.40 and then at aprice of $2.80. See diagram. The appropriate constant elasticity demand curve is Q = 87.2P-59.Figure 4-4DISCUSSION QUESTIONS1. Define the term elasticity. How does this concept help to explain the general shape and slope of a demand curve?2. True or false: The price elasticity of demand changes as price changes along a linear demand curve.Carefully explain your answer.3. If price elasticity of demand changes along a demand curve, how can we say that a demandcurve is relatively elastic or inelastic? Explain.4. It is easy to understand why a large harvest of corn should lower the per unit price. Explain how that could actuallylower the total receipts farmers get from the corn harvest.5. Oil prices increased more than tenfold between 1973 and 1981 as a result of strategies employed by OPEC, an inter-national cartel. Are you surprised that even the richest societies chose to conserve their oil and related energy products? How might people conserve and economize when gasoline, heating fuels, and electricity have become more expensive per unit? How might the increase in gasoline prices in summer 2000 affect behavior?6. “Any demand curve is almost certain to have both an elastic and an inelastic range.” Can you give an exception? Isit realistic through the range of all prices and quantities?7. How does the introduction of the time element affect price elasticities of supply and demand?18 C HAPTER 4: A PPLICATIONS OF S UPPLY AND D EMAND 8. “Knowing how to calculate the slope of a straight line enables you to calculate the elasticity for any point on anycurve.” Discuss the relationship between price elasticity of demand and the slope of the demand curve.9. What is the difference between the price elasticity of demand and the price elasticity of supply?10. Governments interested in maximizing their total revenue have often taxed products like salt, tobacco, andalcohol. What does this suggest about the elasticity of demand for these goods? Why would they be good targets for taxation?11. Evaluate the following charge: If the government grants an industry a subsidy of $1 per unit and the price does notfall by the full $1, then the industry is cheating the consumer.12. Under what circumstances might black markets arise? What can be done about them? Are black markets necessari-ly bad?13. Suppose the government wishes to set a lower bound on the price of wheat. Compare and contrast the methods itcan use to achieve this goal with respect to the what, how, and for whom questions.14. Many economists are against minimum-wage laws. Discuss why a legal minimum wage set above equilibriummay lead to unemployment. How do the price elasticities of demand and supply help to determine the extent of this unemployment? Can people who earn lower wages be helped in ways that will not lead to unemployment?(Think about both sides of the market as you answer this question.)15. According to some estimates, the total revenues from the sale of pornography in Denmark declined by 25 percent inthe year immediately following the liberalization of the censorship laws. From this evidence, some sociologists have determined that legalizing this type of activity reduces the demand for it. Do you agree?Why or why not? What effects on the supply side might be deduced?16. What factors are likely to make demand for a commodity either elastic or inelastic? What factorsare likely to influence elasticity of supply?17. How do you think a minimum-wage law might affect the market for unskilled labor? For skilled labor?ESSAY QUESTIONS1. The Brazilian government used to destroy a substantial portion of its coffee harvest to increase its revenue fromcoffee exports. What conditions are essential to make this type of policy economically beneficial for the country? 2. A witness in a recent congressional hearing argued that consumers budgeted a fixed amount of expenditure for theproducts of his industry. Assuming his statements to be correct, what is the elasticity of demand for the industry’s products? Why?3. On a straight-line demand curve, point out the ranges where demand is elastic, inelastic, and unitary elastic.Why does the elasticity vary along a straight-line demand curve? Draw a graph that relates these regions to the slope of a total revenue curve.4. Consider two markets, the apple market and the orange market. Draw a supply-and-demanddiagram for each market. Indicate the equilibrium price and quantity of P0 and Q0, respectively.a. If there were an outbreak of an apple disease, illustrate the new equilibrium price and quantity in the applemarket by P1, Q1.b. How might this affect the orange market? Show these effects on your diagram.Redraw the original diagram for the apple market. Now suppose the government wishes to encourage the production of apples and gives the producers of apples a subsidy of x dollars per apple.c. Indicate the new equilibrium price and quantity in the apple market by P2, and Q2, respectively.d. Explain whether the equilibrium price will increase or decrease by more or less than the amount of the subsidyper apple.e. Shade in the total subsidy the government will pay to the apple industry each period.f. Describe how this subsidy will be shared between consumers and producers.5. The supply and demand curves for wheat are very inelastic. Those for sugar are very elastic. If a sales tax of $1per unit is put on each of these goods, in which case will the incidence fall largely on the consumer and in which case largely on the producer? In which case is the revenue raised by the tax higher? Use diagrams to illustrate your answers.6. Elasticity is the same as slope. Comment on the validity of this statement.7. Explain the relationship between the elasticity of demand and revenue of a business.。

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(含考研

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(含考研

13.1复习笔记 13.2课后习题详解 13.3考研真题详解
14.1复习笔记 14.2课后习题详解 14.3考研真题详解
附录课后习题详解
第16章政府税收和 支出
第15章比较优势和 贸易保护主义
第17章促进市场更 富效率
第18章环境保 护
第19章效率与 公平:重大权 衡
15.1复习笔记 15.2课后习题详解 18.3考研真题详解
4.1复习笔记 4.2课后习题详解 4.3考研真题详解
5.1复习笔记 5.2课后习题详解 5.3考研真题详解
附录课后习题详解
6.1复习笔记 6.2课后习题详解 6.3考研真题详解
7.1复习笔记 7.2课后习题详解 7.3考研真题详解
附录课后习题详解
8.1复习笔记 8.2课后习题详解 8.3考研真题详解
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16.1复习笔记 16.2课后习题详解 16.3考研真题详解
17.1复习笔记 17.2课后习题详解
18.1复习笔记 18.2课后习题详解
19.1复习笔记 19.2课后习题详解 19.3考研真题详解
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这是《萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(含考研真题)》的读书笔记模板,可以替 换为自己的心得。
本书特别适用于参加研究生入学考试指定考研参考书目为萨缪尔森《微观经济学》的考生,也可供各大院校 学习萨缪尔森《微观经济学》的师生参考。萨缪尔森所著的《经济学》是有史以来发行量最大、至今在全球范围 内仍然被广泛采用的经济学教科书。为了帮助学生更好地学习这本教材,我们有针对性地编著了它的配套辅导用 书(均提供免费下载,免费升级):1.萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(含考研真题) 2.萨缪尔森《微观经济学》(第19版)笔记和课后习题详解(含考研真题)[视频讲解]3.萨缪尔森《微观经济 学》配套题库【名校考研真题(视频讲解)+课后习题+章节练习+模拟试题】4.萨缪尔森《宏观经济学》(第19 版)笔记和课后习题详解(含考研真题)[视频讲解]5.萨缪尔森《宏观经济学》配套题库【名校考研真题(视 频讲解)+课后习题+章节练习+模拟试题】萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(含考研真 题)严格按照第18版教材内容进行编写,共分19章,每章由三部分组成:第一部分为复习笔记,总结本章的重难 点内容;第二部分是课(章)后习题详解,对第18版的所有习题都进行了详解的分析和解答;第三部分为考研真 题详解,精选近年考研真题,并提供了详细的解答。

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(不完全竞争及其极端形式——垄断)【圣才出品】

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(不完全竞争及其极端形式——垄断)【圣才出品】

第9章不完全竞争及其极端形式——垄断9.1 复习笔记一、不完全竞争模式1.不完全竞争的含义如果一个企业能够明显地影响其产品的市场价格,那么,该企业就是一个“不完全竞争者”。

当个别卖者在一定程度上具有控制某一行业的产品价格的能力时,该行业就处于不完全竞争之中。

不完全竞争并非指某一企业对其产品的价格具有绝对的控制力。

一个不完全竞争者对其价格的确拥有某些、但又绝不是全部的决定权。

另外,决定价格的自由度在不同的行业之间也有差异。

在某些不完全竞争行业,垄断力量的强度是非常微小的。

2.不完全竞争与完全竞争的比较如图9-1所示,对于完全竞争而言,其市场需求曲线是一条水平线,完全竞争的企业能够沿着它的水平曲线出售它想要出售的全部产品,而不会压低市场价格。

而对于不完dd全竞争而言,其市场需求曲线是一条向右下方倾斜的曲线,即较高的销售量会压低价格。

图9-1 完全竞争与不完全完全竞争与不完全竞争的具体比较如表9-1所示。

表9-1 完全竞争与不完全竞争市场的比较3.不完全竞争的三种类型(1)垄断生产者,同时,没有任何一个行业能够生产出相近的替代品。

完全垄断在今天是罕见的。

实际上,许多典型的垄断案例仅仅存在于那些受政府保护的产业。

垄断的另一个重要的例子是获得当地公用事业的特许经营权,例如一家提供自来水的公司。

在这样的例子中,仅有一家卖者提供这项服务,而且没有相近的替代品。

(2)寡头寡头是指市场上只有少数几个卖者,从而对市场价格具有一定的影响力的市场结构。

寡头产业在经济中是相对普遍存在的,特别是在制造业、交通及通信等部门中。

例如,虽然在汽车业有各种各样不同的汽车类型,但汽车制造公司却为数不多。

(3)垄断竞争垄断竞争是指一个产业中有许多卖者生产具有差别的产品。

这一市场结构与完全竞争相似,市场上有许多卖者,但任何一个卖者都没有太大的市场份额。

它与完全竞争不相同的是:由不同企业销售的产品并不相同。

差别产品在重要的特征上表现不同。

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(现代经济中的市场与政府)【圣才出品】

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(现代经济中的市场与政府)【圣才出品】

第2章现代经济中的市场与政府2.1 复习笔记一、市场——看不见的手1.市场市场是与社会分工和商品生产紧密联系在一起的,是商品经济的产物。

它既是商品交换的场所和地点,是商品交换关系的总和,同时也是一种市场机制。

(1)市场是商品交换的场所。

在商品经济社会中,企业生产所需要的生产资料等各种资源,消费者所需要的各种消费品,都必须通过市场的交换活动才能得到;企业生产出的各种产品,也只有通过市场才能从生产领域进入到消费领域。

因此,没有市场,就没有商品经济的运行和发展。

(2)市场是商品交换关系的总和。

在商品经济社会中,社会上一切重要经济活动,都是通过市场进行的。

因而,市场成了商品生产者、经营者、消费者之间相互联系的纽带,它集中反映了这三者之间的经济联系和利益关系。

离开了这三者之间的经济联系和利益关系,离开了市场,生产者、经营者、消费者之间物质利益就无法得到合理的协调。

(3)市场是买者和卖者相互作用并共同决定商品和劳务的价格和交易数量的机制,此时市场的概念等同于通常所说的市场机制。

作为市场机制,市场以价格、供求和竞争三位一体的互动关系为基础。

2.价格价格是物品的货币价值,代表了消费者与厂商愿意交换各自商品的条件。

市场经济中,由价格来协调生产者和消费者的决策。

较高的价格趋于抑制消费者购买,同时刺激生产;而较低的价格则鼓励消费,同时抑制生产。

价格在市场机制中起着平衡作用。

从这样的意(1)价格调节社会资源配置。

在市场经济条件下,经济资源在社会上的流动与变化,主要由市场价格来调节。

(2)价格促进企业改进技术和改善经营管理。

一般来说,合理的价格,能够真实地反映和考察各个企业的经营管理水平及经济效益的状况。

(3)价格引导并调节消费的方向与结构。

除了非经济因素对其变化发生影响以外,一般来说,在消费者收入总量稳定的条件下,消费结构的变化主要取决于消费者所需要购买的各种消费品与劳务的市场价格。

(4)价格调节社会物质利益分配。

市场上价格的变化与调整,实际上是物质利益的变化与调整。

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(市场如何决定收入)【圣才出品】

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(市场如何决定收入)【圣才出品】

第12章市场如何决定收入12.1 复习笔记一、收入与财富1.收入(1)个人收入与国民收入在衡量一个人或一个国家的经济状况时,最常用的两个指标是收入和财富。

收入指的是一定时期内(通常为一年)的工资、利息收入、股息和其他有价物品的收益。

市场经济中的收入以工资、利润、租金和利息等形式分配给生产要素的所有者。

所有收入的总和是国民收入,国民收入中最大的部分是劳动收入,其形式为工资、薪金和附加福利。

剩余部分是各种形式的财产收入:租金、净利息、公司利润和业主收入,这部分基本上包括了小企业主的收入。

(2)政府对个人收入分配的作用政府在国民收入分配中还发挥着重要作用。

首先,政府通过税收和其他收费征收了国民收入的很大一部分。

其次,政府又将其所征得的税收反过来再支付给社会。

各级政府以转移支付的形式向社会提供收入。

转移支付是政府向个人提供的一种不需要用商品或服务加以回报的支付。

转移支付中最大的一项是对老年人的社会保险,此外还包括失业保险、农业补贴和福利开支。

个人收入等于市场收入加上转移支付。

市场收入大部分来自工资和薪金;少数富人的市场收入来自于财产权益。

政府转移支付主要是用于支付老年人的社会保险。

2.财富财富是人们在某一时点所拥有的资产的货币净值。

财富是一个存量,而收入是单位时间中的流量。

家庭的财富包括有形财产(房屋、汽车、其他耐用消费品及土地),还有金融资产(如现金、储蓄、债券和股票)。

所有有价值的东西都叫做资产,而所有欠他人的东西都称为负债。

总资产和总负债的差额称为财富或净财富。

二.边际生产率决定投入的价格1.生产要素的需求(1)生产要素需求的性质要素需求与消费品需求有两个主要差别:①要素需求是派生需求;②要素需求是相互依赖的需求。

首先,普通消费者的需求和企业作为投入品的需求之间有着本质的差别:消费者需要最终产品,是因为这些消费品都能直接地提供快乐或效用。

而像企业投入,却并不是因为它们能直接地提供满足,企业购买投入品是因为它能够通过使用这些要素而得到最终产品和相应收入。

萨缪尔森18版微观经济学原理笔记

萨缪尔森18版微观经济学原理笔记

Unit11)经济学economics 研究的是一个社会如何利用稀缺的资源生产有价值的商品,并将它们在不同的人中间进行分配2)经济学两大核心思想:物品和资源是稀缺的,社会必须有效地加以利用两大主题稀缺和效率3)经济品economic goods4)稀缺scarcity 相对于需求,物品总是有限的5)效率efficiency 最有效地利用社会资源以满足人类的愿望和需要在不会使其他人境况变坏的前提下,如果一项经济活动不再有可能增进任何人的经济福利,则该项经济活动就被认为是有效率的6)经济学的精髓之一承认稀缺性是一种现实存在,并探究一个社会如何进行组织才能最有效地利用其资源7)微观经济学microeconomics 主要研究作为单个实体的市场、企业、家庭的行为;宏观经济学macroeconomics 研究经济的总体运行二者共同构成现代经济学的核心8)科学方法scientific approach计量经济学econometrics后此谬误the post hoc fallacy不能保持其他条件不变failure to hold other things constant合成谬误the fallacy of composition9)经济学的最终目的:改善人们的日常生活条件10)经济组织的三个经济问题:生产什么,如何生产,为谁生产生产什么和生产多少,如何生产,为谁生产11)实证经济学(positive economics)经济社会的事实规范经济学(normative economics)涉及价值判断12) 配置稀缺资源的制度和机制市场经济market economics 主要由个人和私人企业决定生产消费的经济制度自由放任经济laissez-faire 政府不对经济决策施加任何影响指令经济command economics 政府作出有关生产和分配的所有重大决策混合经济mixed economics 既带有市场经济的成分也带有指令经济的成分13)投入inputs 生产物品和劳务的过程中使用的物品或者劳务;另一个名称为生产要素factors of production土地自然资源,生产过程中大自然赋予人的礼物劳动人们花费在生产过程中的时间和精力资本一个经济体为了生产其他的物品而生产出来的耐用品专业化的资本品积累是经济发展必不可少的要素产出outputs 生产过程中创造的各种有用的物品或者劳务产出什么,产出多少?如何产出?为谁生产和分配这些产出?14)生产可能性边界production-possibility frontier PPF在知识技术和可投入品数量既定的条件下,一个经济体所能得到的最大产量。

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(含考研真题)(15-19章)【圣才出品】

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(含考研真题)(15-19章)【圣才出品】

第14章附录市场和经济效率附录课后习题详解一、概念题1.局部均衡和一般均衡答:(1)局部均衡是指某一局部市场上的供求平衡时的一种状态。

局部均衡分析研究的是单个的市场、居民或企业的行为,其前提是将其他市场和经济其他部分的行为视为既定。

(2)一般均衡是指所有相关市场上的供求(比如对商品市场、劳动力市场、信贷市场等)都同时实现平衡时的一种状态。

一般均衡同时决定了所有相关市场的价格和供求数量。

一般均衡分析考察的是所有的居民户、企业和市场如何同时相互作用,以解决如何生产,生产什么和为谁生产的问题。

2.配置(或帕累托)效率答:配置效率,有时也称帕累托效率,是指这样一种状态:任何改变都不可能使一个人的境况变好,而又不使别人的境况变坏。

当经济系统实现帕累托效率时,经济运行是有效率的;反之,不满足帕累托效率的经济运行结果就是缺乏效率的。

根据帕累托效率标准,可以对资源配置状态的任意变化做出好与坏的判断。

如果对既定资源配置的状态予以改变,而这种改变使得至少有一个人的境况变好,同时其他人的境况没有因此变坏,则认为这种变化增加了社会福利,或称帕累托改进。

很显然,如果对于某种既定的资源配置状态,不存在任何对资源配置的帕累托改进使得福利增进,则此状态,即为帕累托效率状态。

3.效用可能性边界(UPF)答:效用可能性边界又称“效用可能性曲线”,表示在既定资源条件下,不同消费者所能达到的最优效用水平组合的集合。

效用可能性曲线上的点表示在既定资源和技术条件下,消费者的最大效用的组合。

效用可能性曲线右上方的区域,表示在既定资源和技术条件下,无法达到的区域,称“效用不可能区域”。

效用可能性曲线左下方的区域,表示在既定资源和技术条件下,没有达到最优效用的区域,称“无效率区域”,这时,可以在不影响其他消费者效用水平的条件下增加某个消费者的效用。

4.有效率的一般均衡的关键条件:边际效用(S MU )与价格(S P )成比例;边际成本(S MC )与价格(S P )成比例;所以边际效用(S MU )与投入品的边际成本(S MC )成比例。

萨缪尔森经济学Economics第十八版 18th 课后概念、习题答案7

萨缪尔森经济学Economics第十八版 18th 课后概念、习题答案7

C H A P T E R 7A n a l y s i so f C o s t sCHAPTER OVERVIEW AND TEACHING TIPSThis chapter brings into focus the wide range of cost measures used by economists: total cost, fixed cost, variable cost, average total cost, average fixed cost, average variable cost, and marginal cost.Minimum production costs for a firm are represented along a total cost schedule, which is a function of the level of output. Inputs used in their least-cost combination link the production function with the cost curves, and it is the ability to adjust the employment of inputs that provides the distinction between the two components of short-run total cost: variable cost and fixed cost. The major objective here is for students to obtain a solid understanding of an economist’s perspective of cost accounting, so that subsequent descriptions of market structure will make sense. The student is expected to use tables and diagrams to develop an understanding of both specific examples and more general representa- tions of cost concepts.Chapter 7 also provides a brief introduction to accounting practices. The introduction here is short, covering only two basic tools—the balance sheet and the income statement. The balance sheet is a snapshot of financial health; it reflects the economic condition of an economic entity at some prescribed point in time. The income statement, by wayof contrast, is a motion picture, reflecting growth over a given period of time; it describes the path a firm takes between two different balance sheets.LEARNING OBJECTIVES1. Define and describe total cost, fixed cost, variable cost, marginal cost, and average cost, explainingwhat these measures of cost are designed to reflect and how they are related to one another.2. Derive the associated average and marginal cost statistics from total, fixed, and variable cost.3. Explain the link between productivity and cost.4. Demonstrate precisely why marginal cost always intersects average cost at the minimum of any U-shaped averagecost curve.5. Demonstrate why production costs are minimized when inputs are hired in combinations such that the ratios of theirmarginal products to their prices are all equal.6. Explain carefully the information that a balance sheet is intended to convey. List the major categories appearing onthe two sides of a balance sheet, and indicate the meaning (or definition) of each of those categories.7. List the major items appearing on an income statement. Indicate the information that an incomestatement is intended to convey.8. Explain the role of depreciation and opportunity cost in the correct and accurate construction ofan income statement.9. Define the term opportunity cost and apply it to management decisions made by firms and individuals SUGGESTED ANSWERS TO QUESTIONS IN THE TEXT1. a. .344b. At the end of 1959 his average was .346. His average for 1960 was .316. Since his average in 1960 was belowhis lifetime average the 1960 average pulled his lifetime average down.2. MC and AVC do not change; TC, AC, and AFC shift up. Minimum occurs where MC = AC = $60 at 5 units.2930 C HAPTER 7: A NALYSIS OF C OSTS 3. AC above (below) MC means that the next increment lowers (increases) the average; i.e., AC is falling (climbing).Only when MC = AC is AC neither rising nor falling; i.e., it is at its minimum.4. With a volunteer army the government must be concerned about attracting soldiers. People will agree to enlistonly when the wages they are paid cover their opportunity costs. If service is compulsory, the government has no such constraints on its wage scheme.5. a. Fixed cost equals 15 $12 = $180. MC is the cost of the labor required for each unit increase in output: $30,$25, $20, $30, $50, $70, $90. Variable cost is total labor times the wage: $30, $55, $65, $l05, $l55, $225, $315.b.Doubling the wage increases AC and MC (doubles, in fact, MC but not AC).c.Doubling productivity cuts MC and AC in half. (Factor prices and productivity both influence cost curves.)6. a.Average costs are minimized when marginal cost equals average cost; AC is falling where MC is minimized.b.AFC = FC/output; FC is fixed so as output increases AFC falls.c.AC is rising whenever MC>AC, but AC is falling when MC<AC, even if MC is rising.d.The absence of a market does not imply the absence of value.e.The least-cost rule collapses to this only in very special circumstances. The firm minimizes costs when theratios of marginal product to input price are equal for all inputs.7. The income statement would look something like:Net sales $10 millionLess: costs $9million Net income $1million Less: dividends $0Addition to retained earnings $1 million8.Assets Liabilities and net worth(end of year, millions) (end of year, millions)1999 2000 1999 2000Liabilities 0Net worth$50$51Total$50$51Total$50$51DISCUSSION QUESTIONS1. Explain what is meant by the terms fixed cost, variable cost, marginal cost, and average cost.2. Define the following concepts of costs and discuss how they are related to one another: TC, VC, FC, MC, AC, AFC,AVC.3. Why is it that the MC curve always intersects the AC curve at the minimum point of the AC curve? Why is thisimportant?4. “Opportunity cost is a construction of academia that has no relevance to the daily life of a firm, an entrepreneur, orthe average individual.” Discuss this statement and provide examples to illustrate your a rguments.5. What is the purpose of the income statement? What steps are necessary to translate a figure for sales into a figurefor net earnings after taxes? A figure for sales to a figure for retained earnings? Explain.6. What is depreciation? Outline several ways in which it might be computed for accounting purposes and for tax pur-poses. Can different tax accountings actually favor more rapid growth for a firm? Explain.7. Does an income statement always provide a true summary of a firm’s cash transactions? Why or why not?8. What does a balance sheet show? Describe how the fundamental accounting identity comes into play.9. “The law of diminishing returns is a production principle; hence it has nothing to do with the cost curves.” Is thisstatement true? Discuss.10. What are the opportunity costs of a new parking garage that your university is considering building? Explain.11. Is it true that in the long run fixed costs are always zero? Explain why or why not.ESSAY QUESTIONS1. Suppose that it is known that FC = $10 and that TVC = 0, 1, 5, 8, 15 for Q = 0, 1, 2, 3, and 4, respectively. Derive aproduction table with columns depicting TC, FC, VC, MC, AC, AFC and AVC.C HAPTER 7: A NALYSIS OF C OSTS 312. Draw a U-shaped AC curve and then draw its corresponding MC curve. Describe the relationship between thesetwo curves. If marginal cost is rising, must it be above average costs?3. Define the term marginal cost. What is the relationship between diminishing returns and the marginal cost curve?Explain.4. How is AC computed? How do AFC and AVC differ? Illustrate these relationships graphically.5. Why should price equal opportunity costs in a well-functioning market?6. “The concept of marginal cost has great importance for welfare economics. The resources ofsociety are being efficiently allocated and used only if there is an equality of marginal costs across goods produced everywhere in the country.” Discuss why this statement is true.7. a.What is a balance sheet? Explain what it means for a balance sheet to balance.b.What is an income statement? How, if at all, is it related to the balance sheet?c.Does a year-end addition to earnings retained in a business necessarily imply an equalincrease in thecompany’s cash? Why or why not?8. The balance sheet of Simplified Corporation contains the following items: common stock $8000, inventory $700,cash $500, accounts payable $1000, plant and equipment (less allowance for depreciation) $7000, bonds payable $3000.a. Calculate retained earnings (the only item missing above).b. What other information would you need to calculate Simplified Corporation’s net earnings after taxes?c. Arrange these items in proper balance-sheet form.9. An oil company buys a tanker at a cost of $200 million. It is estimated that the tanker will be obsolete in 8 yearsand will have a scrap value of $1.6 million.a. If the straight-line method of depreciation is used, how much depreciation will be charged each year on theincome statement?b. How will this asset be shown on the balance sheet at the end of 5 years?10. Particular Engines Ltd. is incorporated as of January 1, 1985. It sells 10,000 shares of common stock at$100 per share. It buys new a plant and equipment worth $500,000 and pays $250,000 for a small engine-manufacturing company whose net assets, consisting only of plant and equipment, are valued at $200,000.During the year, the company purchases $200,000 of material, pays wages of $100,000, and makes sales of $500,000-all in cash. It depreciates its plant and equipment on an assumed average life of 10 years.At year end, its inventory is valued at$50,000, and a dividend is paid of $50,000.Draw up (a) an income statement for 1985 for Particular Engines Ltd. and (b) a balance sheet as of December 31, 1985.11. a. Arrange the following items into a balance sheet, under the appropriate headings and subheadings. (Figuresrefer to thousands of dollars.)Accounts Payable = 80 Accounts receivable = 120Cash = 40 Common stock = 150Inventories = 60 Plant and equip = 200Depreciation allowance = 70 Retained earnings = ?Bonds payable = 50b. What is the net worth of the company?c. No dividend was paid during the last year. A stockholder suggested that retained earnings beingwhat they were, a dividend of $50 should be declared. Comment.d. Bond interest of $5 was paid during this last year. Another stockholder suggested that if dividends were beingpassed over, then bond interest ought not to have been paid either. Comment on this suggestion.12. Discuss the sense in which depreciation allowances on the asset side of the balance sheet do or do not representan available pool of liquid assets to retire debt or replace equipment. Compare and contrast a sinking fund to retire debt with an allowance for depreciation.13. Explain the relationship between MC and AC. Explain what happens when MC equals AC.14. Explain what happens to AC when MC is greater than AC.15. Is it possible for AC to be falling and MC to be increasing?。

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(经济学基础知识)【圣才出品】

萨缪尔森《微观经济学》(第18版)笔记和课后习题详解(经济学基础知识)【圣才出品】

第1章经济学基础知识1.1 复习笔记一、经济学概述1.经济学的定义经济学是研究人与社会如何使用稀缺的生产性资源,生产出有价值的物品或劳务,并把它们分配给社会的各个成员的一门学科。

其中所包含的最基本的思想为:资源是稀缺的,社会必须以有效率的方式加以利用。

2.经济学研究的基本问题经济学研究的三个基本问题是:生产什么,如何生产以及为谁生产。

(1)生产什么商品和生产多少?一个社会必须决定,在诸多可能的物品和劳务之中,每一种应该生产多少以及何时生产。

例如决定是利用有限的资源生产更多的消费品,还是应当生产较少的消费品和较多的投资品,从而让明天拥有更多的产出和消费。

(2)如何生产物品?一个社会必须决定谁来生产,使用何种资源,以及采用何种生产技术。

(3)为谁生产?生产出来的产品和劳务用什么样方式分配到社会的各个成员中,即怎样分配所生产出的产品。

3.经济学的双重主题稀缺与效率是经济学的双重主题。

经济社会中的生产资源也叫生产要素,主要包括:资本(其价格为利息)、土地(其价格为地租)、劳动(其价格为工资)。

稀缺是指资源相对于人们无限的需求而言,总是有限的;效率是指最有效地使用社会资源以满足人们的愿望和需求。

正是由于资源稀缺性的存在,使得人们必须考虑如何使用有限的相对稀缺的生产资源来满足无限多样化的需要,这就是所谓的“经济问题”。

4.资源的使用效率及其变动经济学除了“生产什么、如何生产以及为谁生产”这三个基本问题外,还研究以下三方面的内容:(1)社会稀缺的资源是否得到充分使用;(2)社会资源总量的变动;(3)货币的稳定性。

二、资源配置和经济制度1.市场经济市场经济是指资源配置由市场供求所决定的经济,是一种主要由个人和私人企业决定生产和消费的经济制度。

价格、市场、盈亏、刺激与奖励的一整套机制解决了“生产什么、如何生产和为谁生产”这一基本问题。

在市场经济中,企业采用成本最低的生产技术(如何生产),生产那些利润最高的商品(生产什么)。

萨缪尔森经济学Economics第十八版 18th 课后概念、习题答案18

萨缪尔森经济学Economics第十八版 18th 课后概念、习题答案18

CHAPTER OVERVIEW AND TEACHING TIPS This chapter applies the microeconomic theory that we have developed throughout the text to a “real world” problem:How does an economy decide how to use its natural resources? Societies have addressed this question for centuries,some deciding that nature is wild and in need of taming through technology, and others fearing the inherent power of nature and its mysterious forces. In either case, the situation calls for allocation of scarce resources, so economists should be able to provide some answers!Section I kicks off with discussion of Malthus and population growth, and the impact of increasing population on living standards and environmental quality. Section II presents some alternative ways of categorizing natural resources and describes market allocation mechanisms. The final section addresses the problem of externalities, which occur when production imposes costs on outside individuals or on society at large. When externalities occur, the market has failed because demand or supply cannot capture the true costs and benefits of actions. As we learned in the last two chapters,this tends to lead to a role for government in the marketplace.Chapter 18 ties together many of the themes that you have been developing all semester. It relies on an understand-ing of allocation through the market mechanism, on industrial structure and the impact of market failure on resource allocation, and on the role of government when externalities occur and those externalities extend beyond local, state, and national borders. Y ou can use this material as a sort of capstone to the course, and as a review of the concepts that you have taught.LEARNING OBJECTIVES1.Discuss reasons why the theory on overpopulation growth developed by Malthus has had such a great impact on the way people think about resource use. Explain why Malthus’s somewhat gloomy predictions have not come about.2.Describe the relationship between the economy and the environment, as well as the relationship between a country’s development and the quality of its natural environment.3.Differentiate between appropriable and inappropriable resources, and between renewable and nonrenewable resources. Explain how decisions concerning the optimal use of environmental resources differ depending on the category in which they fall.4.Review the path of resource prices over the past several decades. Respond to the notion that resource prices should tend to increase as population increases and demand for those resources shifts to the right.5.Define the term externality . Describe the mechanism by which inefficiencies develop in markets when external costs and benefits are present.6.Use cost-benefit analysis to find the socially efficient quantity of pollution that will occur. Construct a diagram that illustrates this decision-making process. Explain how contingent valuation might be used to place values on envi-ronmental resources.7.Review alternative government policies that are designed to correct externalities, such as emission fees, markets for pollution permits, private contracts, and liability rules. Compare the pros and cons of these alternatives.8.Discuss the difficult problems raised by global public goods .SUGGESTED ANSWERS TO QUESTIONS IN THE TEXT1.Renewable resources are those whose services are replenished regularly; nonrenewable resources are fixed in total supply. Renewable = water, forests; nonrenewable = fossil fuels.87C H A P T E RP r o t e c t i n g t h eE n v i r o n m e n t1888C HAPTER18: P ROTECTING THE E NVIRONMENT 2.An inappropriable resource is one whose use is free to the individual but costly to society. Long Island Sound is aninappropriable resource, because firms can dump trash in it for free, but this dumping imposes a cost on the rest of society. This is inefficient, because externalities are imposed on a third-party group that must pay a portion of the production costs even though they may not be involved in the market transaction.pare the arithmetic progression 2,4,6,... with the geometric progression 2,4,8,16,32... As long as the multipleused in the geometric progression is greater than 1, the geometric progression will always be greater than the arithmetic progression. As the numbers get larger, any multiple of those numbers will get larger.Hence, with a geometric progression the difference between the numbers is getting larger; with an arithmetic pro-gression the difference between the numbers is constant.4.Food production per capita would be given by the equationFPC = Total Food Production / Total PopulationIf the numerator is increasing arithmetically while the denominator is increasing geometrically, by your answer to #4 above the food per capita will eventually fall.5.Yes, towns may have an incentive to compete for “high quality” residents using local public goods. Towns withgood schools and nice beaches will be more attractive to residents and firms that are looking to relocate. Towns want to attract residents and firms that are going to bring tax dollars and other inputs to enhance the life of the com-munity. This indicates that we should return responsibility for these local public goods to the hands of local policy-makers. However, in some areas, inner-city neighborhoods for example, it is difficult to return responsibility to the residents, who may be besieged by crime and other problems. In Hartford, Connecticut, for example, the local school board at one point turned responsibility for schools over to a private firm. The point here is that local author-ity in these areas is good but is not the answer for all communities.e your own judgment on these.7.This technique is not too reliable, since people have a tendency to overvalue an item that they do not actually haveto pay for.8. a.Although many economists in the U.S. like to rely on the market to solve problems, most are willing to agreethat externalities occur when markets fail. That is, environmental problems often occur when property rights are difficult, if not impossible, to define.b.Economists often recommend market solutions because they cause smaller distortions in the distribution ofresources than would occur in a setting with full information. However, this does not mean that many economists fail to recognize the need for government-mediated solutions in some cases.c.Economists often rely on the price mechanism because, as mentioned above, it leads to a more efficient alloca-tion of resources. However, economists do recommend other sorts of solutions, such as emissions fees, in some instances.d.The most difficult economic questions involve achieving a balance between these two goals in distributingresources. On the one hand, most economists want to “make the most” out of a system’s endowment of resources.On the one hand, many of us are concerned with distributing that endowment of resources in a fair way.9.See Figure 18-1. In this case, what is “best” for each country individually leaves the world with a level of pollutionthat is higher than the social optimum. In such cases, a cooperative solution is more efficient than the competitive solution.DISCUSSION QUESTIONS1.Review the ideas that Thomas Malthus had about population growth. What important factor did Malthus ignore?2.Consider the relationship between population and living standards. Think of some areas of the world that have highpopulations and poor living standards; think of some areas of the world that have high populations and high living standards.3.If a resource is inappropriable, will market failure always occur? Does the government always have to step in toallocate an inappropriable resource efficiently?4.Why is it that the prices of natural resources have not skyrocketed over the course of this century, as a greater worldpopulation is now demanding greater and greater amounts of these resources?5.What is the difference between public and private goods? Why can’t private markets provide a good like nationaldefense?C HAPTER18: P ROTECTING THE E NVIRONMENT89Figure 18-1e a diagram to illustrate the determination of a socially optimal level of pollution. Does this mean that societydesires some amount of pollution? Why would this be?pare alternative government policies designed to correct externalities. What are the pros and cons of each?8.Why have markets for tradeable pollution permits become a popular solution for pollution problems? Whathappens if a single firm buys all of the permits that exist?9.What is a global public good? Explain why these externalities are so difficult to manage. How did the KyotoProtocol attempt to deal with the problem of a global public good?10.David Roodman writes, “But if the market’s spontaneous origin has led many to underestimate its value, the mar-ket’s power has dazzled others into overlooking its shortcomings.” [The Natural Wealth of Nations. New York: W.W.Norton, 1998.] Interpret this statement. What have market forces done for the standard of living in the U.S.this century? What are the shortcomings of this progress?ESSAY QUESTIONS1.Throughout history, technology has had incredibly important impacts on the way that we live and work. In spite ofthe tremendous advantages technology brings, it also carries problems and responsibilities. What are some of these? Why might unchecked technological advance cause social problems?2.What is the difference between renewable and nonrenewable resources? During the 1970s, OPEC, an internationaloil cartel, dominated the market for oil and controlled the world supply so as to keep prices high. What happened to this cartel? If oil is a nonrenewable resource, how did OPEC lose control over the world market?3.Why has the world price of oil not skyrocketed in this century, as more and more people are using this source ofenergy? What are the sources of the recent price increases that occurred in the spring 2000?4.Is health care a public good? Are significant externalities generated by the provision of health care? What are thenature of these externalities?5.If health care is a public good, why does government not provide health-care services for everyone? Explain.pare direct controls with economic incentives as alternative methods for government to use in limiting (or pro-moting) externalities. Which type of incentive do you find most appealing?7.State the Coase theorem. Why did Coase believe that private individuals could take care of externalities?8.What important assumptions underlie the Coase theorem? Do these assumptions characterize markets in the UnitedStates today? If so, should we get the government out of the business of regulating externalities and allow private markets to operate?9.Do you think that contingent valuation is a good way to place value on our natural resources? Do individuals havean incentive to be truthful?。

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第11章不确定性和博弈论
11.1 复习笔记
一、风险和不确定性经济学
1.投机原理
(1)投机的原因及含义
一般而言,市场上的产品价格每月都在波动,劳动、土地、机器和燃料等投入品的价格常常有很高的不稳定性;竞争对手的行为也无法提前预知。

企业当前投资的实质在于为未来的利润积攒财富,以备应对未来的不确定性。

投机包括对有价值物品或商品的买卖,是从市场价格的波动中谋取利益的一种活动。

通常,一个投机者现在买入一种商品,为的是将来在这种商品价格上涨时卖出,以期获得利润。

投机是一种风险行为,即使是有经验的投机者有时也会因为错误的估计而遭受损失。

(2)投机的形式
①套利和地区价格形式
最简单的投机活动是降低或消除地区差价。

在这种情况下,商人在某一市场买入的同时,以较高的价格在另一市场卖出。

这种活动被称为套利,它在一个市场上买入一种商品或资产,为的是马上在另一个市场上卖出,从而在价差中获得利润。

套利活动就是同时与不同地区的经纪人通话,以找出微小的差价,力图通过低价购买和高价售出来获取利润。

套利活动有助于拉平完全相同的产品在不同市场上的价格差别。

套利体现了“看不见的手”的作用,即在获取利润的动机的诱惑下,消除不同市场价格差异,促进市场功能更加有效地发挥作用。

投机致力于确立某种不同的时间和空间上的价格范式。

但未来难以预测,从而使这种价格范式不那么完美,即总是处在一种不断受到破坏而自身又不断地重新构建的均衡之中。

投机揭示了看不见的手的法则在起作用。

通过拉平供给量和价格,投机实际上在提高经济效率。

通过将商品从数量丰盛的时期转移到数量稀缺的时期,投机商在价格和边际效用低的市场购进商品,又在价格和边际效用高的地方卖出。

投机商们在追求他们私人利益(利润)的同时,提高了公共经济福利(总效用)。

③投机的经济作用和影响
投机市场不仅从时间上和空间上促进了价格及配置形式的改善,还有助于风险的转移。

这些任务都是由那些想从价格变动中获利的投机商所完成的。

事实上,这表明了看不见的手在起作用,即将商品从其数量丰盛(价格低)时期向数量稀缺(价格高)时期进行重新配置。

理想的投机对于减少消费量的变化有重要的作用,而且,在个人都表现出边际效用递减的情况下,投机可以提高总体效用和分配效率。

投机活动的经济作用就是将各种商品从数量丰富的时期“运送”至商品稀缺的时期。

这种“运送”将会跨越空间、时间或者不确定的自然因素。

具体而言,投机就是在商品数量充足、价格低的时间或地点买进,然后在商品数量稀缺、价格高的时间或地点卖出。

投机市场的一个重要功能是让人们通过套期保值分摊风险。

套期保值是通过对所拥有的一种商品作对冲交易来降低风险。

套期保值通过作对冲交易来回避价格波动的风险。

2.风险、不确定性和保险
(1)人们的风险偏好
一般地说,人们都不愿冒风险,总是想要避免各种消费和收入的不确定性。

在其他条件相同的情况下,相对于不确定的消费水平来说,人们更喜欢做有把握的事情。

也就是说,
的活动能够导致经济福利的改善。

一般说来,若一个人为损失一定量的收入而产生的痛苦感大于他为得到同等数量的收入而产生的满足感,则他就是一个风险规避者。

(2)保险与风险分摊
尽管风险规避者都要努力避免风险,但风险并不会因此而被消除。

市场机制通过风险分摊来应付各种风险。

所谓风险分摊就是将对一个人来说可能是很大的风险分摊给许多人,从而使每个人所承担的风险很小。

风险分摊的主要形式是保险。

保险公司通过集中各种不同的风险来分摊风险:它为数以百万计的住宅、生命或汽车提供保险。

保险公司的优势在于,对个人来说是难以预料的事件,对整个人群来说则具有很强的可预见性。

保险将风险从风险规避者或风险较大者的一方,转移到偏好风险者或较容易承担风险者的一方,保险能够减轻和分散风险。

3.资本市场与风险分担
分散风险另一种方式是经由资本市场来进行。

有形资本的资金所有权可以通过企业所有权这个媒介,将风险在很多的所有者之间进行分摊。

通过将风险性资产的所有权分散到众多的所有者身上,资本市场便可以分散风险,并且能够提供比单个的所有者大得多的投资和承担大得多的风险。

4.信息市场失灵
由于市场失灵,在现实中会出现许多不确定性和风险。

市场失灵的两个重要因素是:“逆向选择”和“道德风险”。

当存在这些因素时,市场就可能会给出错误的信号,从而破坏激励机制,甚至有时还会瓦解市场机制。

在这样一些场合,政府很可能就会介入并提供社会保险。

(1)保险市场的失灵
保险市场正常运转需要一些条件。

首先,必须存在大量的随机事件。

只有这样,保险公司才能将各种不同的随机事件合并起来,并将风险分散,从而使那些对个人来说是很大的风险,能够变成对许多人来说是很小的风险。

其次,各随机事件还必须是相对独立的。

任何一家谨慎的保险公司都尽力使其承保的范围分散到各种不同的和相对独立的风险上。

再者,保险公司对于这样的随机事件必须具有足够的经验,这样,才能准确地预期和估计损失。

最后,相对来讲,保险必须排除道德风险。

当保险减小了个人躲避和防止风险的动力,从而扭曲了损失发生的概率时,便会发生道德风险的问题。

除了道德风险会导致保险市场失灵以外,逆向选择也会导致市场失灵。

由于逆向选择,人们得不到私人保险,或者,会出现令人难以接受的定价方式。

当风险最大者成为最可能购买保险的人群时,逆向选择便发生了。

(2)社会保险
当市场失灵严重以致私人保险不能提供足够的保险项目时,这时就需要由政府提供的强制性社会保险来发挥作用。

政府具有税收和调节权力,加上有能力通过扩大保险的覆盖面以避免逆向选择,因而政府的保险能够增进社会福利。

社会保险的一个重要例子是失业保险。

首先,保险公司不能提供失业保险,因为道德风险很严重(如果获益丰厚的话,人们很可能选择失业);其次,存在严重的逆向选择(那些经常失业的人更愿意多购买失业保险);再者,每个人的失业风险的增减并不独立(它们通常随经济周期的衰退而同步出现);最后,人们在失业时需要有一张安全网,以减轻失业的痛苦。

因此,政府经常介入和提供失业保险。

政府不能防止道德风险问题,但却能借助全面覆盖保险范围的社会保险计划来防止逆向选择。

社会保险的另一个重要例子是老年人医疗保险。

由于健康的人不愿投保,而投保人主
要都是高成本人群,因而会出现逆向选择的问题。

逆向选择对于老年人更加严重,因为生命中最后一年的医疗费用很可能要占人生总医疗费用的较大比例。

为了避免逆向选择,政府对老年人提供全面的保险计划,医疗费用由保险费和全部在职人员所交纳的税金来加以支付。

二、博弈论
1.博弈论及其基本概念
(1)博弈论的含义
博弈论所分析的是两个或两个以上的参与者选择能够共同影响每一参加者的行动或策略的方式。

经济学家利用博弈论来研究垄断者们的互动、工会与管理层的争议、国际贸易政策、国际环境协议、名誉以及其他诸多问题。

博弈论还可以用来研究政治、福利和日常生活。

(2)博弈论的基本概念——以价格战为例
①博弈的描述
假如市场上的供给只由两个企业来提供,它们正在决定是否进行毁灭性的低价格经济战。

每一企业都具有相同的成本和需求结构,而且每个企业都可以选择运用正常的价格,或采取低于边际成本的价格,从而迫使对手破产,以占领整个市场。

双寡头垄断博弈的特点是,企业利润的获得既取决于自己的战略,也取决于对手的战略。

如图11-1所示,体现两个企业或两个人之间相互作用的有用工具是双方的支付矩阵,这是一种表示双方采取的策略和回报状况的方法。

在支付矩阵中,每一个企业可以在自己的行和列中选择战略。

每个企业有两种选择:是运用正常的价格,还是采取低价格挑起价格战。

将每个竞争者所选择的两种决策组合起来,可以得到四种结果:A是两个企业选择
正常价格的结果,D 是双方均选择低价战价格的结果;B 和C 则是一方采用正常价格,而另一方采取低价战价格的结果。

图11-1 价格战的支付矩阵
每1格子中的数字代表了两个企业的回报情况,即每个企业在四种结果中的获利情况。

左下角的数字是对弈者Amazing 公司的获利;右上角的数字则表示nEwBooks 公司的获利。

由于参与企业是一致的,因而,双方的获利情况势必具有对称性。

②策略选择
博弈论的指导思想是:假设一方在研究另一方的策略,并采取追求自身最大利益行动的时候,另一方如何选择最有效的策略。

在双寡头垄断价格战博弈中,这两家公司在图11-1中的A 格有着共同的最大利益。

当双方都运用正常价格战略时,每个企业将各赚10美元。

而在另一个极端,是双方都采用削价战略、都会遭受最大损失的情况。

在上述两种情况之间,存有两种有趣的战略,即只有一方选择发动价格战。

例如,在结果C 中,nEwBooks 公司坚持正常的价格战略,而Amazing 公司却采取降价战略。

于是,Amazing 公司拥有了市场,可它却损失了大笔的金钱,因为它的售价低于成本。

nEwBooks 公司一直以正常价格销售,而不是对Amazing 公司的策略以牙还牙,其处境反倒要好一些。

③占优均衡。

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