武汉大学宏观经济学期末试题

武汉大学2008-2009学年第二学期期末考试
经济与管理学院 2008级 2009年6月30日
《宏观经济学》试题（A卷）
Principles of Macroeconomics (Paper A)
Instruction
You have two hours to complete this test. Full marks are 100 points. Write your answers on the answer sheet. While you are allowed to answer either in English or Chinese, it would be more graded at a reasonable degree if you choose to do it in English. Read the questions carefully before answering them. Be precise and keep to
the point.
Good luck!
Problem 1 (10 points)
True or False? Explain your answer completely but briefly.
a.(5 points) Consumption, investment, government purchases and net export are Not
sources of Long-term economic growth.
b.(2.5 points) It is one case of moral hazard that a patient is more likely to apply for
health insurance than healthy men.
c.(2.5pionts) According to the theory of efficiency wages, firms who pay wages at
the equilibrium level will operate more efficiently.
Problem 2 (10 points)
Suppose there is a small farming economy that produces corn. In such an economy, 80 bushels (蒲式耳) are consumed, 10 go for government purchases to feed the army, 6 go into domestic investment as increases in inventories, and 11 bushels are exported. In addition, the economy imports 7 bushels of corn and taxes farmers by 12 bushels.
a.What is the GDP of the economy?
b.Calculate private saving, public saving and net capital outflow. Then explain the
relationship between saving and investment.
c.Assuming in the economy, women have worked more hours in producing corn.
How would this affect GDP? Explain the paradox, “When a person marries his or her gardener (园丁), GDP goes down.” Do you think GDP is a good measure of national accounts?
Problem 3 (10 points)
Below are some data about Pizza and Latte (拿铁，一种咖啡).
pute the GDP deflator for each year, using 2006 as the base year.
b.Suppose that the base year for the CPI is 2006. If the CPI basket consists of 400
pieces of pizza and 1000 cups of latte during the three years, compute the CPI for each year. What is the CPI inflation rate from 2007 to 2008?
c.According to your computation, what is the difference between GDP deflator and
CPI?
Problem 4 (15 points)
The Federal Reserve conducts a $20 million open-market purchase of government bonds. The required reserve ratio is 10 percent.
a.What is the money multiplier? How can this purchase affect money supply? What
is the largest possible effect? What is the smallest possible effect? Explain why. b.Show the effects of this purchase in a diagram of money supply and money
demand.
c.Can you find roles of commercial banks and individual depositors in the creation
of money in terms of multiplier formula?
d.What happen to value of money and price level? And what is the impact of this
money expansion on real variables such as output and employment?
Problem 5 (10 points)
Suppose Japanese decided they no longer wanted to buy U.S. assets as before. Using a three-panel diagram used in textbook for open economy, show the following effects of the change.
a.What would happen in U.S. market for loanable funds? In particular, what would
happen to U.S. Interest rates, U.S. saving, and U.S. investment?
b.What would happen in the market for foreign-currency exchange? In particular,
what would happen to the value of the dollar and the U.S. trade balance?
Problem 6 (15 points)
Suppose that the economy is in a long-run equilibrium.
e a diagram to illustrate the state of the economy. Be sure to show aggregate
demand, short-run aggregate supply, and long-run aggregate supply and explain why these curves look like this.
b.Now suppose that a stock market crash causes aggregate demand to fall. Use your
diagram to show what will happen to output and the price level in the short-run.
What happen to the unemployment rate? And in the long run?
c.Now suppose that a war in Middle East drives up the cost of producing oil
products. What are the likely macroeconomic effects of such a change? Explain with the help of appropriate graphs.
Problem 7 (15 points)
a.Suppose the government increases its purchase expenditure by $20 billion, which
finally raises the total demand for goods and services by $100 billion. If we ignore the possibility of crowding out, what would the marginal propensity to consume to be? If we allow for crowding out, would the marginal propensity to consume in this case be larger or smaller than their initial one?
b.Suppose the government reduces taxes by $20 billion, there is no crowding out,
and the MPC is 0.8. What is the initial effect of the tax reduction on aggregate demand? What is the total effect of this policy?
c.How does the total effect of the $20 billion tax cut in part (b) compare to the total
effect of a $20 billion increase in government purchase in part (a)? Why?
Problem 8 (15 points)
Suppose king's weather (好天气) drives down the cost of producing food products. a.Show the impact of such a change in both the aggregate-demand/aggregate-supply
diagram and in the Phillips-curve diagram. What happens to inflation and
unemployment in the short-run?
b.Do the effects of this event imply there is no short-run tradeoff between in
inflation and unemployment? Why or why not?
c.Suppose in the following year, bad weather brings stagflation, and the central
bank pursues contractionary (紧缩性的) monetary policy to reduce inflation. Use the Phillips curve to show the short-run and long-run effects of this policy. How might the short-run costs of the policy against inflation be reduced?
武汉大学2008-2009学年第二学期期末考试
经济与管理学院 2008级 2009年6月30日
宏观经济学（A卷）
Principles of Macroeconomics ( Paper A )
说明:考试时间为2小时，满分为100分。

答案写在答题纸上，可用英文或中文作答。

仔细阅读下面的问题后再简明扼要地作答。

祝你好运！
1．(10分)判断正误，并作简要解释。

a.消费、投资、政府购买与净出口并不是长期经济增长的源泉。

b.病人比健康的人更有可能购买健康险，这是一种道德风险情形。

c.根据效率工资理论，支付均衡水平工资的企业将会更有效率。

2. (10分)假设现在有一个小农经济。

该经济生产一些谷物，也进口一些谷物，假设进口量是7蒲式耳。

这些谷物中，80蒲式耳被消费掉，10蒲式耳作为政府购买来培养军队，6蒲式耳为增加国内存货的私人投资。

此外，税收为12蒲式耳。

a.该经济的GDP是多少?
b.计算私人储蓄、公共储蓄和净资本流出，再解释储蓄和投资之间的关系。

c.假设该经济中妇女更多地参与谷物生产，这会如何影响GDP？解释悖论“当
一个人和他或她的园丁结婚时，GDP下降了”。

你认为GDP是国民收入核算的一个良好的指标吗？
3. (10分)以下是关于比萨饼和拿铁咖啡的一些数据：
a.以2006年为基年，计算每年的GDP平减指数。

b.设2006年为基年，如果三年间的CPI篮子包括400个比萨饼和1000杯拿铁咖啡，
计算各年的CPI。

从2007到2008年的CPI通货膨胀率是多少？
c.根据你的计算，GDP平减指数（GDP deflator）和CPI之间有何差异？
4. (15分)美联储进行公开市场业务，购买了2000万美元的政府债券。

法定准备金率是10％。

a.货币乘数是多少? 这一购买如何影响货币供给？可能的最大和最小效应各是
多少？解释之。

b.用货币供求图说明这一购买的效应。

c.你能用乘数公式给出商业银行和单个存款人在货币创造中的作用吗？
d.货币的价值和物价水平有何变化？这种货币扩张对产量与就业这样的实际变
量产生什么样的影响？
5. (10分)假设日本人决定不再象从前那样购买美国资产。

利用书上开放经济中的三幅图，说明这一变化的效应。

a.美国的可贷资金市场会发生什么？尤其是，美国的利率、储蓄和投资会有何
变化？
b.外汇市场会有何变化？尤其是，美元和美国贸易余额会有何变化？
6. (15分)假设经济处于长期均衡。

a.作图解释该经济的这一均衡状态。

说明总需求、短期总供给、长期总供给，
并解释为什么这些曲线会是如此形状。

b.现在假设股票市场崩溃引起总需求下降。

利用图形说明短期内产出和物价水
平会发生什么变化？长期又如何呢？
c.现在假设中东战争提高了石油产品的生产成本。

这一变化可能会引起什么宏
观经济效应？利用适当的图形解释。

7. (15分)
a.假设政府增加其购买支出200亿美元，这最终使得商品和劳务的总需求增加了
1000亿美元。

如果我们不考虑挤出效应的可能性，边际消费倾向将是多少？
如果考虑挤出效应，边际消费倾向此时会比先前大还是小呢？
b.假设政府减少税收200亿美元，没有挤出效应，MPC是0.8。

税收减少对总需
求的初始效应是多少？这一政策的总效应又是多少？
c.b部分20亿美元税收减少的总效应，和a部分政府购买增加的总效应相比如
何？为什么？
8. (15分)
假设好天气降低了食品的生产成本。

a.同时用总供给总需求和Phillips曲线，说明这一变化的影响。

短期内通货膨胀
和失业有何变化?
b.这一事件的效应是否意味着在通货膨胀和失业之间不存在权衡？为什么是或
不是？
c.假设在接下来的一年，恶劣天气引起了滞胀，央行实行紧缩性的货币政策来
减少通货膨胀。

利用Phillips曲线说明这一政策的短期和长期效应。

如何能够减少这一反通胀政策的短期成本?
武汉大学2008-2009学年第二学期期末考试
经济与管理学院 2008级 2009年6月30日
宏观经济学（参考答案）
Principles of Macroeconomics ( A: Solutions) Solution to Problem 1 (10 points)
a.True. They play a role in sustaining full employment. Sources of long term growth
are labor, capital, human capital, and technology.
b.FALSE. It is one case of adverse selection that a patient is more likely to apply for
health insurance than healthy men(2 points).
c.FALSE. According to the theory of efficiency wages, firms who pay wages above
the equilibrium level will operate more efficiently(2 points).
Solution to Problem 2 (10 points)
a.GDP=C+I+G+NX=80+6+10+(11-7)=100
b.Sprivate=Y-C-T=100-80-12=8, Spublic=T-G=12-10=2, NCO=NX=4; Sprivate +
Spublic=8+2=I+ NCO=6+4
c.GDP increased when women reduced their unpaid housework which were not
included in GDP. The paradox means that GDP goes down because paid jobs
become unpaid housework which is not included in GDP. GDP is not a good
measure of national accounts for so much is ignored in GDP.
Solution to Problem3 (10 points)
Solution to Problem 4(15 points)
a.With a required reserve ratio of 10 percent, the money multiplier could be as high
as 1/.10 = 10,if banks hold no excess reserves and people do not keep some additional currency. So the maximum increase in the money supply from a $20 million open-market purchase is $200 million.The smallest possible increase is $20 million if all of the money is held by banks as excess reserves.
b.
Solution to Problem 5
(10 points)
a. If the Japanese decided they no longer wanted to buy U.S. assets, U.S. net capital
outflow would increase, increasing the demand for loanable funds, as shown in the following figure. The result is a rise in U.S. interest rates, an increase in the
quantity of U.S. saving (because of the higher interest rate), and lower U.S.
domestic investment.
b. In the market for foreign exchange, the real exchange rate declines and the
balance of trade increases.
Solution to Problem 6(15 points)
0(Low) (High) (High) (Low) M 1M 2
a. The AD curve slopes downward because of the wealth effect, the interest-rate effect, and the exchange-rate effect. The short-run AS curve slopes upward which can be explained by the stick-wage theory, the sticky-price theory and the
misperception theory. The long-run AS curve is vertical because of monetary neutrality.
b. A stock market crash leads to a leftward shift of aggregate demand. The equilibrium level of output and the price level will fall. Since the quantity of output is less than the natural rate of output, the unemployment rate will rise above the natural rate of unemployment.
c. A war in Middle East drives up the cost of producing oil products, which leads to a leftward shift of short-run aggregate supply. The equilibrium level of output will fall ,but the price level will rise. Since the quantity of output is less than the natural rate of output, the unemployment rate will rise above the natural rate of unemployment.
Quantity of output
Natural rate of output AD 1
2
Natural rate
of output Quantity of Output
Price Level 0Equilibrium
price
Solution to Problem 7(15 points)
a. If we ignore the possibility of crowding out, 1/(1 – MPC )=5, and MPC=4/5. If we
allow for crowding out, MPC will be larger than their initial one. When MPC is larger than 4/5, multiplier effect will drive up the total demand more than $100 billion, while the crowding out effect will drive down the total demand. As a result, the total effect is an increase of AD equal to $100 billion.
b. The initial effect of the tax reduction of $20 billion is to increase aggregate
demand by $20 billion x 4/5 (the MPC) = $16 billion. Additional effects follow this initial effect as the added incomes get spent. The multiplier is 1/(1 –4/5) = 5, so the total effect is $16 billion x 5 = $80 billion.
c. Government purchases have an initial effect of the full $20 billion, since they
increase aggregate demand directly by that amount. The total effect of an increase in government purchases is thus $20 billion x 5 = $100 billion. So government purchases lead to a bigger effect on output than a tax cut does. The difference
arises because government purchases affect aggregate demand by the full amount, but a tax cut is partly saved by consumers, and therefore does not lead to as much of an increase in aggregate demand.
Solution to Problem 8(15 points)
a. The following figure shows the effects of king's weather. The short-run
aggregate-supply curve shifts to the right, reducing the price level and increasing the quantity of output.The short-run Phillips curve shifts to the left. In both
diagrams, the economy moves from point A to point B. In equilibrium, both the inflation rate and the unemployment rate decline. Natural rate of output
Quantity of output
AD 2
1
2
b.The effects of this event do not mean there is no short-run tradeoff between
inflation and unemployment, as shifts in aggregate demand still move the
economy along the short-run Phillips curve.
c.Contractionary monetary policy to reduce inflation will make the economy move
along a short-run Philips curve from A to B in the short-run and reach C in the long-run with the fall of expected inflation. The short-run costs of disinflation, which arises because the unemployment rate is temporarily above its natural rate, could be reduced if the Fed's action was credible, so that expectations would
adjust more rapidly.。