威廉森《宏观经济学》(第3版)课后习题详解(s第3篇 经济增长)

1 / 34第18章 通货膨胀、菲利普斯曲线和中央银行承诺18.1 复习笔记一、菲利普斯曲线1．菲利普斯曲线（1）20世纪50年代，菲利普斯从英国的经验数据中发现，名义工资的变化率与失业率负相关。

又因为名义工资的变化率与其他货币价格的变化率高度正相关，因此，失业率与总体经济活动的趋势偏离高度负相关，进一步又得出通货膨胀率与总体经济活动的趋势偏离正相关。

将菲利普斯曲线定义为通货膨胀率与实际总产出的趋势偏离正相关。

如果用Y T 表示趋势实际总产出，用Y 表示现实实际总产出，那么，菲利普斯曲线可以用如下关系描述：i ＝H （Y －Y T ）式中，i 为通货膨胀率；H 为增函数，如图18-1所示。

2 / 34图18-1 菲利普斯曲线（2）对由经验得出的菲利普斯曲线关系的评论如图18-2所示，从美国的经验数据中可以得到以下结论：①明显的菲利普斯曲线关系并不存在于所有的数据集中。

若将1947～2012年作为一个考察期，难以辨别出菲利普斯曲线关系，但若将样本期分成三个时期，菲利普斯曲线就开始显现出来。

也就是划分成1947～1969年、1970～1984年和1985～2012年这三个时期，分别是低通货膨胀时期、高通货膨胀时期和低通货膨胀时期。

②菲利普斯曲线是不稳定的。

在1947～1969年和1970～1984年期间，菲利普斯曲线向上移动，而在1985～2012年，菲利普斯曲线向下移动，而且变得不那么陡直。

3 / 34图18-2 菲利普斯曲线的移动（3）通货膨胀发生的原因①基本上所有的恶性通货膨胀都能追根溯源到大量政府预算赤字的存在。

政府需要高额支出，但公众可能不愿意用税收来为这些支出买单；政府可能也不想增加税收。

于是，政府会求助于通过印钞为政府赤字筹资。

4 / 34②温和的通货膨胀不一定是由高额政府预算赤字造成的，未必需要求助于通货膨胀税。

货币供给增长率的意外提高（货币意外）引起通货膨胀率的意外上升，能使劳动力供给量和总产出暂时增加。

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3.1 考虑教材中第3.2节中1θ<时的模型。

（a ）在均衡增长路径上，()A A g t *=g，其中A g *是A g 的均衡增长路径值。

利用这个事实以及方程（3.6）()()() L t B a L A t A t θγ=g［］推导均衡增长路径上()A t 的一个表达式，把它用B 、L a 、γ、θ和()L t 来表示。

（b ）应用对（a ）问的答案以及生产函数()()()()1L Y t A t a L t =-，求均衡增长路径上()Y t 的表达式。

求最大化均衡路径产出的L a 的值。

答：（a ）关于产出和知识的生产函数为：()()()()1L Y t A t a L t =- （1）()()()() 1L t B a L t t A A θγθ=<g< p="">［］（2）在均衡增长路径上，()()()//1A A t A t g n γθ*==-g （3）对（2）两边除以() A t ，即：()()()()1/L t A t Ba L t A A t γθγ-=g（4）将（3）（4）联立得：()()()()()11/1/(1)L L Ba L t t n A n Ba L t A t γθθγγγγθγθ--??=-?=-??上式简化为：()()()()1/11/L A t Ba L t n θγγθγ-??=-??（5）（b ）将（5）代入（1）得：()()()()()()()()(1/11/1/11)()())1(/1/11/1L L L L Y t Ba L t n a L t B n a a L t θγγθγθγθθγθγ---+-??=--??- -?=? ??［］两边取对数，可得：()()()()()()()()ln 1/1ln 1//1ln ln 1/11ln L L Y t B n a a L t θθγγθγθ??=--+-+-+-+一阶条件为：经过简单的数学运算求L a *：（6）θ值越大，新知识在生产函数中的作用越大。

第三单元产品市场和货币市场的一般均衡本单元所涉及到的主要知识点：1.投资的边际效率与投资函数；2.IS曲线；3.货币供求与均衡利率的决定；4.LM曲线；5.两市场的同时均衡：IS－LM模型。

一、单项选择1.当利率降得很低时，人们购置债券的风险〔〕。

a.将变得很小；b.将变得很大；c.可能变大，也可能变小；d.不变。

2.如果其他因素既定不变，利率降低，将引起货币的〔〕。

a.交易需求量增加；b.投机需求量增加；c.投机需求量减少；d.交易需求量减少。

3.假定其他因素既定不变，在非凯恩斯陷阱中，货币供应增加时，〔〕。

a.利率将上升；b.利率将下降；c.利率不变；d.利率可能下降也可能上升。

4.假定其他因素既定不变，在凯恩斯陷阱中，货币供应增加时，〔〕。

a.利率将上升；b.利率将下降；c.利率不变；d.利率可能下降也可能上升。

5.假定其他因素既定不变，投资对利率变动的反响程度提高时，IS曲线将〔〕。

a.平行向右移动；b.平行向左移动；c.变得更加陡峭；d.变得更加平坦。

6.假定其他因素既定不变，自发投资增加时，IS曲线将〔〕。

a.平行向右移动；b.平行向左移动；c.变得更加陡峭；d.变得更加平坦。

7.假定其他因素既定不变，货币的投机需求对利率变动的反响程度提高时，LM 曲线将〔〕。

a.平行向右移动；b.平行向左移动；c.变得更加陡峭；d.变得更加平坦。

8.假定其他因素既定不变，货币供应增加时，LM曲线将〔〕。

a.平行向右移动；b.平行向左移动；c.变得更加陡峭；d.变得更加平坦。

9.如果资本边际效率等其它因素不变，利率的上升将使投资量〔〕a.增加；b.减少；c.不变；d.可能增加也可能减少。

10.利率和收入的组合点出现在IS曲线右上方，LM曲线的左上方的区域中，那么表示〔〕。

a.I>S，L<M；b.I>S，L>M；c.I<S，L<M；d.I<S，L>M。

11.利率和收入的组合点出现在IS曲线右上方，LM曲线的右下方的区域中，那么表示〔〕。

宏观经济学课后习题答案问题1：什么是宏观经济学？它的研究对象是什么？宏观经济学是一门研究整体经济运行的学科。

它关注的是经济中的总体现象和经济运行的规律，包括国民经济的总体规模、增长速度、物价水平、就业水平、物资供求关系等。

宏观经济学的研究对象是整个经济系统，即国民经济的各个部门和各个经济主体之间的关系。

问题2：GDP的定义是什么？它的计算方法有哪些？GDP（国内生产总值）是一个国家或地区在一定时间内所生产的最终产品和服务的总价值。

它可以通过产出法、收入法和支出法进行计算。

•产出法：根据产品的产出量和售价来计算GDP。

主要包括产业增加值、商品增值税和净关税三个部分。

产业增加值是国内企业生产商品和服务所增加的价值，商品增值税是销售商品过程中增加的税费，净关税是进口商品关税减去出口商品的关税。

•收入法：根据国民收入的构成来计算GDP。

主要包括工资、利润、利息和租金等因素。

•支出法：通过对整体需求的衡量来计算GDP。

主要包括消费支出、投资支出、政府支出和净出口四个部分。

问题3：什么是通货膨胀？它有哪些影响因素？通货膨胀是指货币购买力下降，物价水平普遍上涨的现象。

通货膨胀导致货币价值的贬值，影响经济体制和社会生活的稳定。

通货膨胀的影响因素包括：1.需求拉动型通货膨胀：需求过高导致价格上涨。

当居民收入增加，需求上升，商品供不应求时，市场价格会上涨，从而导致通货膨胀。

2.成本推动型通货膨胀：成本上升导致价格上涨。

生产成本的上升，如劳动力成本、原材料成本等，将推动产品价格上涨，从而导致通货膨胀。

3.货币发行过多：当国家通过货币发行扩大经济增长，而没有相应的经济增长，会导致货币供应过剩，从而出现通货膨胀。

4.供给不足：当出现自然灾害、生产能力下降或政策限制等因素，会导致供给不足，进而推动商品价格上涨，引发通货膨胀。

问题4：什么是经济增长？有哪些推动经济增长的因素？经济增长指的是一个国家或地区在一定时间内经济总量的扩大。

1 / 37第1章 导 论1.1 复习笔记一、宏观经济学1．宏观经济学的研究对象宏观经济学的研究对象是众多经济主体的行为。

它关注的是消费者和企业的总体行为、政府的行为、单个国家的经济活动总水平、各国间的经济影响，以及财政政策和货币政策的效应。

2．宏观经济学与微观经济学的联系与区别（1）联系微观经济学家与宏观经济学家都在使用非常相似的研究工具。

宏观经济学家用来描述消费者与企业的行为、目标与约束，以及他们之间如何相互影响的经济模型，是根据微观经济学原理建立起来的，而且在分析这些模型和拟合数据时通常都用微观经济学家所用的方法。

2 / 37（2）区别宏观经济学的研究对象有别于微观经济学，宏观经济学侧重于总量研究，强调的问题主要是长期增长和经济周期。

微观经济学主要针对单个消费者或者企业的行为选择。

二、国内生产总值、经济增长与经济周期1．国内生产总值（gross domestic product ，GDP ）国内生产总值是一国在某一特定时期在境内生产的产品和服务的数量。

GDP 也表示那些对国内产出作出贡献的人挣得的收入总量。

实际GDP 是针对通货膨胀进行调整后的总产出衡量指标。

2．经济增长（long-run growth ）经济增长率是一个国家当年国内生产总值对比往年的增长率。

经济正增长一般被认为是整体经济景气的表现。

长期增长是指一国长期的生产能力和平均生活水平的提高。

3．经济周期（business cycles ）经济周期是指总体经济的短期上下波动，或经济的繁荣与衰退。

3 / 37三、宏观经济模型1．宏观经济模型及其假设宏观经济模型是用来解释长期经济增长、经济周期存在的原因、以及经济政策在宏观经济中应发挥的作用的模型。

确切的说，宏观经济模型的基本构造是用来描述下列特征的：（1）经济中相互影响的消费者与企业。

（2）消费者希望消费的一组商品。

（3）消费者对商品的偏好。

（4）企业生产商品可采用的技术。

（5）可利用的资源。

第一章宏观经济学的科学一、选择题1.下列哪一项不是宏观经济学家研究的主要问题( B )A.经济增长B.供需的价格弹性C.通货膨胀D.充分就业2.下列不正确的是 ( A )A.经济模型是对经济的精确描述B.经济模型是对经济现象的抽象C.经济模型往往是用数学术语说明变量之间的关系D.经济模型有助于解释经济变量3.经济模型要解释的变量是( C )A.内生变量和外生变量B.外生变量C.内生变量D.既不是内生变量也不是外生变量4.存量是( A )A.某个时点现存的经济量值B.某个时点上的流动价值C.流量的固体等价物D.某个时期内发生的经济量值5.下列各项中哪一个属于存量( C )A.国内生产总值B.投资C.失业人数D.人均收入6.宏观经济学的创始人是( C )A.斯密B.马歇尔C.凯恩斯D.萨缪尔森7.在凯恩斯看来,造成资本主义经济萧条的根源是( B )A.资源短缺B.有效需求不足C.资源配置不当D.技术落后8.下列哪一本著作对现代宏观经济学的产生起了最为重要的作用（ C ）。

A.凯恩斯的《货币论》B.马歇尔的《货币、信用与商业》C.凯恩斯的《就业、利息和货币通论》D.亚当.斯密的《国富论》二、名词解释宏观经济学宏观经济学与微观经济学相对，是一种现代的经济分析方法。

它以国民经济总体作为考察对象，研究经济生活中有关总量的决定与变动，解释失业、通货膨胀、经济增长与波动、国际收支及汇率的决定与变动等经济中的宏观整体问题，所以又称之为总量经济学。

宏观经济学的中心和基础是总供给-总需求模型。

具体讲，宏观经济学主要包括总需求理论、总供给理论、失业与通货膨胀理论、经济周期与经济增长理论、开放经济理论宏观经济政策等内容。

对宏观经济问题进行分析与研究的历史十分悠久，但现代意义上的宏观经济学直到20世纪30年代才得以形成和发展起来。

宏观经济学诞生的标志是凯恩斯于1936年出版的《就业、利息和货币通论》。

宏观经济学在20世纪30年代奠定基础，二战后逐步走向成熟并得到广泛应用，60年代后的“滞胀”问题使凯恩斯主义的统治地位受到严重挑战并形成了货币主义、供给学派、理性预期等学派对立争论的局面，90年代新凯恩斯的形成又使国家干预思想占据主流。

第3章经济周期的衡量一、复习题1．经济周期的主要明显特征是什么？答：经济周期的明显特征是：经济周期围绕着实际GDP的趋势波动。

用与现实的实际GDP非常吻合的平滑曲线来表示实际GDP的趋势，这种趋势意味着部分实际GDP可归因于长期增长因素。

其余未分析的，即对趋势的偏离，则用经济周期活动来表示。

表示实际GDP的增长趋势的曲线绕着趋势上下变动，波谷是对趋势的最大负偏离，波峰是对趋势的最大正偏离，从而形成衰退与繁荣的经济周期波动。

2．除持续性外，偏离GDP趋势的三个重要特征是什么？答：偏离GDP趋势的三个重要特征是：（1）偏离实际GDP趋势的时间序列很不稳定。

（2）实际GDP围绕趋势波动的幅度没有规律性。

一些波峰和波谷意味着对趋势的巨大偏离，而另一些波峰和波谷则意味着对趋势的小幅偏离。

（3）实际GDP围绕趋势波动的频率没有规律性。

实际GDP中波峰和波谷之间的时间跨度变化很大。

3．解释预测长期GDP为何困难。

答：预测长期GDP困难的原因：（1）实际GDP围绕趋势波动的幅度没有规律性，一些波峰和波谷意味着对趋势的巨大偏离，而另一些波峰和波谷则意味着对趋势的小幅偏离。

（2）实际GDP围绕趋势波动的频率没有规律性。

实际GDP中波峰和波谷之间的时间跨度变化很大。

（3）偏离实际GDP趋势的时间序列很不稳定。

总之，实际GDP波动的不稳定使这些波动难以预测，而且不稳定性也使得转折点何时发生难以预测，而波幅和频率的无规律则意味着难以预测衰退和繁荣的强度和时间长短。

4．总体经济活动变量的联动为何重要？答：尽管实际GDP波动具有不规律的形式，但宏观经济诸变量一起波动的格局显示出了较强的规律性，这些波动格局称为联动。

通过以时间序列图或散点图的形式为两个经济变量偏离其趋势的百分比作图，或通过计算偏离趋势的百分比标准差，就可判别联动。

联动性很重要，因为联动性的规律表明，经济周期是大同小异的。

经济周期的这一性质可能产生分析经济周期的一般理论，这一可能的新理论不同于以往的理论，即：将每一个经济周期都看作是一系列独特条件的结果再进行经济周期的研究。

Chapter 3Business Cycle MeasurementTeaching GoalsChapter 3 stresses the importance of observation as a foundation for scientific exploration in macroeconomics. Because there are mountains of data measurements about the macroeconomy, we need to begin to organize these data in a way that we can begin to look for regularities in the economy—regularities that we hope to explain. The cornerstone of business cycle analysis is deviations from trend in real GDP. Students must first understand the difference between long-run trends and deviations from trend in real GDP.One of the most exciting things about the study of business cycles is the observation that each of these recurring cycles is not unique. Because successive business cycles are more alike than they are different, we have the hope of providing an explanation of business cycles that can consistently be applied to each new cycle we encounter. These business cycle regularities, the “stylized facts” of business cycles, provide us with the first clues about the nature of the typical cycle. Although students may take some time to digest and remember these facts, it is important to be clear about the motivation for cataloging these facts. The plan of study of this text is to view the business cycle as a puzzle that we hope to solve. Our task is much the same as a detective trying to solve a murder mystery. The first task is to collect clues. The clues in the study of business cycles are the regularities chronicled in this chapter. Later on we will begin to encounter “suspect” causes of business cycles. In order to solve the mystery, we need to deduce the “who,” “what” and “why” of our mystery. We cannot begin the deduction process before first collecting the clues. Students need to understand this detective process. Otherwise, the clues presented in this chapter will be nothing more than a laundry list that they must memorize.Classroom Discussion TopicsTo get the ball rolling it might be useful to ask the students about whether they have concerns about recessions. Is the economy currently in a recession? When was the economy most recently in recession? The obvious candidate is the recession of 2001. One interesting point concerns the duration of the recession. Real GDP declined only in the first three quarters of 2001. However, even as of this writing in early 2007, many people perceive that the U.S. economy is still in a recession. This concern possibly reflects the fact that, through the third quarter of 2003, employment has continued to decrease and has only moderately recuperated since, as noted in the table below. Should we revise the definition of a recession by basing it on movements in employment or the unemployment rate? Which set of data provides a better picture of the overall well-being of the economy?Chapter 3 Business Cycle Measurement 21 Real GDP and Employment, 2000–2003QuarterReal GDP(millions of 2000 dollars)Employment/Population Ratio(%)2000q1 9,695.6 64.62000q2 9,847.9 64.62000q3 9,836.6 64.22000q4 9,887.7 64.32001q1 9,875.6 64.32001q2 9,905.9 63.82001q3 9,871.1 63.52001q4 9,910.0 63.02002q1 9,977.3 62.82002q2 10,031.6 62.82002q3 10,090.7 62.82002q4 10,095.8 62.52003q1 10,126.0 62.52003q2 10,212.7 62.32003q3 10,398.7 62.12003q4 10,467.0 62.22004q1 10,566.3 62.32004q2 10,671.5 62.32004q3 10,753.3 62.42004q4 10,822.9 62.52005q1 10,913.8 62.42005q2 11,001.8 62.72005q3 11,115.1 62.82005q4 11,163.8 62.82006q1 11,316.4 62.92006q2 11,388.1 63.02006q3 11,443.5 63.12006q4 11,506.5 63.3Macroeconomics is primarily concerned with business cycles and economic growth. Ask the students which of these two topics is most important. A typical comparison is between the possibility of completely eliminating recessions as opposed to increasing the rate of growth by a half of one percent or so. If they could pick only one of these advances, which would they pick? Some simple calculations reveal the apparent dominance of more growth over eliminating business cycles. Ask them if they believe that there is any other cost of a recession other than the value of lost GDP. In particular, emphasize that GDP fluctuations hide a lot about fluctuations at the household level.Another potential discussion centers on the murder mystery analogy. If the students were rounding up the usual suspects of business cycle causes, which suspects would they pick? One part of detective work involves theories and hunches about what might have happened. Another less glamorous part of detective work involves ruling out some of the suspects. How can studying the clues eliminate a suspect from consideration? Emphasize the point that much of the organization of the text revolves about the possible elimination of suspected causes of business cycles based on the evidence.22 Williamson • Macroeconomics, Third EditionOutlineCyclesI. BusinessA. Features of Business Cycles1. Peaks2. Troughs3. Turning Points4. Amplitude5. Frequency6. PersistenceB. Business Cycle Regularities1. Business Cycles Are Persistent2. Deviations from Trend Are Choppy3. Variability in Amplitude4. Variability in FrequencyII. ComovementA. Time Series ObservationsB. Correlation1. Time Series Comparisons2. Scatter Plots3. Correlation CoefficientC. Cyclical Properties1. Procyclical2. Countercyclical3. AcyclicalD. Timing1. Leading2. Lagging3. CoincidentE. The Index of Leading IndicatorsF. Variability of Time SeriesIII. Components of GDPA. Consumption1. Procyclical2. Coincident3. Less Variable Than GDPB. Investment1. Procyclical2. Residential and Inventory Investment Lead GDP3. More Variable Than GDPChapter 3 Business Cycle Measurement 23IV. Nominal VariablesA. The Phillips CurveB. Aggregate Price Level1. Procyclical Since World War II2. Sometimes Countercyclical3. Lags GDPC. Money Supply1. Procyclical2. Leads GDPV. Labor Market VariablesA. Employment1. Procyclical2. Lags GDPB. Real Wage Rates1. Procyclical2. Aggregation ProblemsC. Average Labor Productivity1. Procyclical2. Coincident3. Less Variable Than GDPTextbook Question SolutionsQuestions for Review1. Business cycles are fluctuations about trend in real GDP.2. The time series of deviations from trend in real GDP is quite choppy. There is no regularity in theamplitude of fluctuations. There is no regularity in the frequency of fluctuations.3. The choppiness of fluctuations makes them difficult to predict. Choppiness also makes it difficult totell when a turning point has occurred. The lack of regularity in amplitude and frequency makes it difficult to predict their severity and length.4. Comovement is important because the regularity of such comovements suggests that business cyclesare more alike than different. This property of business cycles suggests that it may be possible to develop a general theory for business cycle analysis. This approach would be in contrast toperforming event studies of each business cycle as if it were a consequence of a unique set ofcircumstances.5. Robert Lucas has suggested, “With respect to qualitative behavior of comovements among [economictime] series, business cycles are all alike.”6. We may discern correlation in time series by observing whether one series tends to be above (below)trend when the other series is above (below) trend. Series that both tend to be above trend and below trend at the same time are positively correlated. When one series tends to be above (below) trend when the other series is below (above) trend, they are negatively correlated.24 Williamson • Macroeconomics, Third Edition7. There is an almost endless list of possibilities. Pairs of variables that are positively correlated includethe fraction of the day in sunlight and the average air temperature, and the amount of time spent studying and a student’s grade point average. Pairs of variables that are negatively correlated include the weight of a vehicle and its gasoline mileage, and the amount of home insulation and heating and cooling expenses.Note that pairs of variables may not be perfectly correlated. For example, some students are able to get good grades without studying that much. Also note that correlation says nothing about direct causality. In the sunlight and air temperature example, the direct cause of both phenomena is the fact that the earth is tilted on its axis and revolves around the sun.8. An index of leading indicators is useful because turning points in the index generally precede turningpoints in real GDP.9. The three characteristics of comovements that are most interesting to economists are whether a seriesis procyclical or countercyclical, whether the series leads or lags real GDP, and whether the series is more or less volatile than real GDP.10. Consumption and investment are both procyclical. Consumption is less variable than real GDP, whileinvestment is considerably more variable than real GDP. Consumption is coincident with real GDP.Some components of investment (residential investment and inventory investment) lead the business cycle.11. The cyclical behavior of the price level can vary across time periods and across countries. In theUnited States, the price level has been procyclical since the end of World War II. The price also tends to lag the business cycle. The money supply is procyclical and leads the business cycle.12. No. The time period 1947–2006 is best characterized as displaying a reverse Phillips curve.13. Employment is procyclical, employment lags the business cycle, and employment is less variablethan real GDP. The real wage is procyclical.Problems1. First we draw a scatter plot of the data as in the figure below.Chapter 3 Business Cycle Measurement 25(a) Although the correlation coefficient does not appear to be very large, x and y are positivelycorrelated.(b) For this part of the problem, we need to draw the data in the form of two time series plots as inthe figure below.They lags the variable x.variable(c) The two time series appear to be characterized by persistence.2. The instructions define booms and recessions as peaks and troughs that exceed 1% of GDP. Althoughthe resolution of the diagram makes it difficult to tell exactly when the 1% threshold is reached, it would appear that we have the following booms and recessions.Time Period Type Magnitude6.2%47–50 Recession3.3%50–53 Boom2.8%53–54 Recession54–55 Boom2.1%4.1%55–58 Recession2.7%60–61 Recession61–67 Boom3.0%3.4%67–71 Recession3.8%71–73 Boom73–75 Recession3.8%3.4%75–79 Boom4.7%81–82 Recession1.7%83–89 Boom1.6%90–91 Recession2.4%97–00 Boom1.8%01 Recession(a) Booms were about as frequent in both periods.(b) Recessions were more frequent in the period 1950–1970 by a margin of 2 to 1.(c) Booms were less strong in the period 1976–2006 by a margin of 2.1% to 3.0%.(d) Recessions were less severe in the period 1976–2006 by a margin of 3.0% to 3.8%.26 Williamson • Macroeconomics, Third Edition3. Higher real GDP is associated with higher consumption spending. Some of consumption spending ison imported goods.4. The positive correlation of real GDP with the index of leading indicators is quite strong. However,there are times (e.g., 1968) when movements in the two series are coincident. In such cases, the index confirms the existence of a turning point, but it fails to predict it.5. Government expenses in the cycle.(a) Difficult to tell: government expenses are clearly more variable in the first half of the sample, butthey are less variable in the second half.(b) No clear comovement emerges here. This can be explained by changing policies or by the factthat governement expenses take a while to plan, pass the legislature, and execute.(c) Sometimes it leads, sometimes it lags. But lags may be so large that they could be falselyinterpreted as leads of the next cycle, see (b).6. Exports in the cycle.(a) Exports are much more volatile than GDP.(b) Exports appear to be procyclical, but not as strongly as other aggregates.(c) There is definitively a lag.7. Series X clearly lags series Y. The two series are almost identical and are shifted in time.8. Productivity (Y/N) and employment (N) are both procyclical and both are less variable than GDP.By definition, real GDP equals productivity times employment. In an expansion, both productivity and employment increase (both are procyclical). Therefore the variability of real GDP is likely to be greater than the individual volatilities of Y/N and N. Productivity is coincident while employment lags the business cycle. For these facts to be consistent, there must be a dominant coincident factor that affects productivity independently from movements in employment itself.9. Both consumption and investment are procyclical and coincident. The key difference is thatinvestment is much more volatile than consumption. Consumer durables provide services over a horizon greater than one year. Some consumer nondurable products, like apparel, provide services well beyond the date of purchase. Services, by definition, are fully utilized at the point of sale. The same kinds of timing considerations that affect business investment are likely to come into play with consumer durables, and to a lesser extent, consumer nondurables. Therefore, it is logical that consumer durable purchases should be more volatile than consumer nondurable purchases and that consumer nondurable purchases should be more volatile than consumption of services.。

第三章生产者选择一、名词解释：生产函数、长期、短期、边际产量、边际生产力递减规律、等产量曲线、等成本线、边际技术替代率、生产要素的最优组合、生产扩张线、规模报酬、会计成木、经济成木、经济利润、正常利润、固定成本、可变成本、边际成本、短期成本、长期成本二、选择题1、当劳动的（L）总产量下降时，（D ）。

A.AP L是递减的；B・AP L为零；C. MP L为零；D・MP L为负；2、如果连续地增加某种生产要素，要总产量达到最人时，边际产量1111线（D ）。

A.与纵轴相交； B •经过原点；C.与平均产量曲线相交； D •与横轴相交；3、当AP L为正但递减时，MP L是（D ）。

A.递减；B・负的；C.零； D •上述任何一种；4、如图4・1所示，厂商的理性决策应在（B ）。

A.3v,Lv7; B-4.5<L<7;C.3<L<4.5; D0vL,4.5;5、列说法屮错谋的一种说法是（B ）oA.只要总产虽减少，边际产量一定是负数；B.只要边际产量减少，总产量一定也减少；C.随着某种生产要素投入量的增加，边际产量和平均产量增加到一定程度将趋于下降，具中边际产量的下降一定先于平均产量。

D.边际产聚曲线一定在平均产罐曲线的最高点与之相交。

6、MPL为负时，我们是处于（D ）。

A.对L的I阶段； B •对K的III阶段；C.对L的II阶段；D・上述都有不是；7、下列是说法中正确的是（D ）0A.生产要素的边际技术替代率递减是规模报酬递减造成的；B.边际收益递减是规模报酬递减造成的；C.规模报酬递减是边际收益规律造成的；D.生产要素的边际技术替代率递减是边际收益递减规律造成的；8、如果以横轴表示劳动，纵轴表示资本，则等成本Illi线的斜率是（B ）oA.P L/P K； B • -P I TP K；C. P K/P L； D • -P K/P L；9、在边际产最发生递减时，如果要增加同样数最的产品，应该（A ）0A.增加变动的牛产要素的投入量； B •减少变动的生产要素的投入量;C.停止增加变动的生产要素； D •同比例增加各种生产耍素；B ・3；1（）、在有效区域屮，等产蜃1111线（A ）。

宏观经济学（第三版）部分习题答案第一章1、答：宏观经济学识将一个国家或一个社会作为一个整体的经济运行主体作为考察对象，它研究的是一个国家经济的总体运行状况，以及政府如何运用经济政策来影响国家整体经济的运行。

宏观经济学家所关心的问题包括以下几个方面：决定一国经济长期增长的经济因素，为什么会出现通货膨胀，失业的存在和自然失业率不断上升的原因，一国经济为什么会出现周期性波动现象，全球经济体系是如何影响一国经济运行的。

宏观经济学以规范与实证的方法研究一个经济体的总量经济问题。

总量问题包括一个国家资源是如何配置的，一国国民收入与就业总量是如何决定的，价格总水平是如何形成的，国民收入在长期增长趋势中为什么会出现周期性波动，等等。

2、答：一个国家宏观经济运行质量一般可以从4个方面进行考察，即国民产出，就业状况，价格变化和对外贸易。

（1）一个国家的经济实力和经济成就最终是以一国的国民产出水平，国民的人均收入水平和经济增长速度为标志。

实际的国民产出的高水平和快速，稳定，均衡的增长是一国宏观经济追求的首要目标。

（2）保持劳动力的充分就业是宏观经济的第二个目标。

就业水平与产出水平密切相关，高产出意味着高就业，即人们能够较容易地寻找到自己愿意接受的报酬水平的工作岗位。

政府一般将高就业与低非自愿失业作为宏观经济的重要目标之一。

（3）维持价格总水平的稳定是宏观经济运行的第三个目标。

价格总水平也与国民产出有较高的相关度。

国民产出增长过快，容易刺激物价的上升，形成通货膨胀的局面；国民产出增长过慢，会减少人们的购买力，从而造成物价总水平的下降，形成通货紧缩的局面。

因此宏观经济追求的目标是高产出与低通胀相对应的经济格局。

（4）宏观经济的第四个目标涉及到一国的对外经济关系。

在开放经济中，一国与别国的经济关系包括商品及劳务的进口与出口，资本的流入与流出，技术的引进与输出等。

因此保持汇率的稳定和进口大致的平衡是各国对外经济方面力求达到的宏观经济目标。