Principles of Macroeconomics
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 (20 points)
True or False? Explain your answer completely but briefly.
a.(5 points) China’s GDP per capita rises quickly, so are the people’s well being of China.
b.(5 points) China’s CPI is a perfect index for the measurement of the price level of the whole economy.
c.(5 points) The opportunity cost of holding money is the nominal interest rate.
d.(5 points) The U.S. stock market is an informationally efficient market.
Problem 2 (30 points)
a.(10 points) Inflation is unpopular, why don’t the political leaders in the world always want to reduce inflation? Why don’t they take 0 inflation rate as their policy target? Do you think a country can costlessly reduce its inflation rate?
b.(10 points) If an increase of government spending of $10 billion raises aggregate demand by $30 billion, if there is no crowding out effect, what is the marginal propensity to consume (MPC)? If there is crowding out effect, will the MPC be larger? Give out the necessary formula you use. Do you think the multiplier model can apply in the reality?
c.(10 points) Why we some times say that , some times we say that . That is why it is an identity in the former case and an equilibrium equation in the latter case. Tell the teacher 3 concepts of “equilibrium GDP”.
Problem 3 (50 points)
a. (10 points) Tell us what do you know about the long run determinants of real GDP. What variables can affect the determinants of real GDP? Try to evaluate the scientificness of this framework that Macroeconomics uses to research economic growth.
b. (10 points) what are the roles (intrinsic static functions, and external effects after injecting some of them into the economy) of money for the economy in Macroeconomics? You should distinct the long run and the shout run in answering this problem. Do you think there is really independence of the central bank as some countries have claimed?
c. (15 points) explain which causes which in the following three equations: (the quantity theory of money) , (the Fisher effect), ( the purchasing power theory of exchange rate. And use , to analyze, if China has a 30% higher money growth rate this year that last year, where the exchange rate between China’s Renminbi and U.S. Dollar will go (under the assumption that other things being equal)? What will be China’s nominal interest rate? Give your reason.
d. (10 points) What are the relations between the multiplier model, the IS_LM model, the AS-AD model, and the Philips Curve? Write out the equations we use to describe them when you discuss the relations between them (you only need to translate the verbal language in the textbook into mathematical language).
e. (5 points) China today often use the legal reserve rate to control money supply. If the banking system now has total reserves of 10 unit, and the reserve rate is 10%. What the money supply will be? If China raises the reserve rate to 20%, what will be the money supply? Assume banks hold no excess reserves and households hold no currency.
【参考答案】
Problem1:
a．F. 因为福利由GDP很好地衡量是需要条件的。即不能收入分配恶化、环境恶化等。
b．F. 很显然，谈不上完美。不仅房价这一整个经济的价格水平无法反映，而且，一些重要的相对价格也无法反映。比如，一些中国生产的电脑品牌的国内价格甚至高于美国。
c．是的。这可以通过一笔货币存款的实际收益率与债券的实际收益率之差来证明。当然，这个答案的成立也是有条件的。
d．显然不是。否则，美国股市就不会出现大跌。
Problem 2:
a.虽然通胀不是令人欢迎的，但令人欢迎的不仅是通胀，因此，领导人在考虑是否降低通长时往往受到其他因素的制约。应该区分，如果通胀仅仅是由于无原因的货币供给过快引起的（比如一些国家试图用通胀来促进经济增长），那么，这种通胀就可以与其他问题分离开来，就应该无条件降低。他们无法把0通胀作为目标的一个重要原因是国际开放。0通胀的实施将会使得一个国家的货币相对通胀国家升值，从而恶化该国的贸易平衡。降低通胀自然是有代价的，可是，如果GDP本身没有什么值得欢迎的（比如极度biased的增长），那么，这种代价可能也称不上是什么代价。
b.MPC=0.7。是。△y＝△G/（1－MPC）。乘数模型不能在经济中使用。
c.恒等表明它们是一个定义式，相等表明它们是一个均衡式。二者的投资的定义是不一样的。前者指实际投资，后者指合意投资。关于均衡GDP的定义可以有三个，甚至更多。一是直接使用GDP=合意消费+合意投资+合意政府购买+合意净出口（这里的均衡概念不涉及价格和利率）。一个是使用IS-LM模型（这里是用利率和GDP来定义）。一是使用AS=AD（这里是用GDP和价格来定义）。也可以考虑有汇率的均衡产出定义。等等。
Problem 3.
a.按照所谓增长利率，它是由劳动力、资本、技术、自然资源决定的。政府政策是决定这些变量的关键变量。这个增长理论的科学性是有争议的。至少，从逻辑上看，难以直接把资本作为与劳动力并列的生产要素。二者性质上存在根本的差异。合理的看法应该是把资本、自然资源作为劳动的手段和对象。
b.货币的交易功能，通胀效应（长期）和产出效应（菲利普斯曲线）。没有什么真正的央行独立性。这一点从美国2008年的危机发生的原因就可以看出。从追问独立于什么，就可以看出。
c.MV=PY中，Y和V是外生变量。现在一般认为是M决定P。但实际上，应该是P决定M。费雪效应中，r是外生的。名义利率由通胀决定。PPP中，e是内生的，但根据汇率制度的不同，e也可能是外生的。人民币将贬值30%。
d.乘数模型考虑利率可变后成为IS曲线。IS-LM模型考虑价格变化后成为AD曲线，AD-AS模型转换考虑空间后为Philips曲线。公式参见课本。
e.100。50。
