经济学原理I(11秋季期中2及答案).doc

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1、姓名学号班级（A 卷）经济学原理 I（2011 年秋季学期） 期中考试 2（A 卷答案）（2011/11/30） 注意：请将所有题目的答案写在答题册上，写在本试题纸上一律无效。一、判断题（判断并简要说明理由，必要时可以用图形。每题4分，共24分）1. 春节期间倒卖火车票导致火车票短缺，损害了效率和公平。错误（1 分）。火车票短缺是由于春节期间车站规定价格（价格上限）下供小于求，从而引 发倒票的套利行为。实际上，倒票者使得火车票价格回到市场均衡价格，反而有利于消除短 缺（2 分）。这一行为有可能促进了效率（使得出价高的买者得到票，从而改进了交换效率）（0.5 分）。虽然票贩子获利有可能带来不公平

2、，但没有倒票者时也并不能保证穷人一定买到 票，即使买到票也需要付出排队等成本，因此倒票是否损害公平也很难说。（0.5 分）2.在美国销售的耐克鞋很多是在中国生产的，制造商向中国工人支付的工资比美国工人低 得多。这一做法同时损害了中国和美国的整体利益，因此不论从哪个国家的利益着想， 都应该禁止耐克公司在中国开厂。错误（1 分）。作为耐克鞋的出口方，中国的企业和工人从中受益，而美国耐克鞋的生产工 人则从中受损。（1 分）与此同时，中国的耐克鞋购买者受损（相对于耐克鞋不出口，但相 对于耐克鞋由美国工人生产则可能受益），美国的消费者和耐克鞋制造商受益（1 分）。无论 对于耐克鞋的出口国（中国）和进口国

3、（美国）而言整体上都是受益。从两国整体利益考虑 不应该禁止耐克在中国开厂。（1 分）3. Consider a country that imports a good from abroad. If demand is perfectly inelastic, consumers do not benefit from trade and there are no gains from trade for this country. (Hint: Use graph.)False(1 point). As the graph below shows, consumers benefit fro

4、m trade by area ABCE. The countrys gains from trade are area BCD. (3 points)DDomestic DemandDomestic SupplyABWorld PriceCDomestic PriceE4. A proper corrective tax (or Pigovian tax) on a market with negative externality reduces the social welfare (or cause deadweight loss) since the reduction in cons

5、umer and producer surplus exceeds the revenue raised by the government. (Use a graph).21False(1 point). The graph below shows the welfare effect of corrective tax. Consumers surplus reduces by area ABCF. Producers surplus reduces by area FCDE. The governments tax revenue is ABDE. So area BCD is the

6、welfare loss within the market. However, the bystanders (those who suffered from negative externality) gain from the tax by area BDCG. As the whole, the social welfare increases by area BGC. This in fact equals to the deadweight loss when corrective tax is absent. (3 points. To get full scores, CS,

7、PS, Tax revenue and bystanders surplus each must be labeled correctly)Social cost, supply cost with corrective taxSupply curve, private costGBAFCPollution cost,EDcorrective taxDemand curve,social and private valueQSO=Q* Q*5. 环境保护法规定：“排放污染物超过国家或者地方规定的污染物排放标准的企业事 业单位，依照国家规定缴纳超标准排污费，并负责治理。征收的超标准排污费必须 用

8、于污染的防治，不得挪作他用。”如果超标准排污费正确反映了污染的社会成本，则 这一规定必定导致污染数量少于社会有效率数量。正确（1分）。如果超标准排污费恰当地反映了企业污染的（边际）社会成本，那么，企业排 放一定数量污染物并交纳相应的排污费就是社会有效率的（2分）。实际上，对这些污染物的 治理成本高于了超标准排污费（否则企业会选择治理而不是交费），即节约的污染成本，导 致污染治理过度，引起社会无效率。（1分）6. A regressive tax (a tax for which high-income taxpayers pay a smaller fraction of their inco

9、me than do low-income taxpayers) must result in a vertical-inequality, because the higher income a person has, the less amount of tax he or she will pay.False (1 point). Although a regressive tax has an average tax rate decreasing with income, but if the speed of this decrease is slower that the inc

10、rease of income, the total amount of tax paid (tax rate multiplied by income) will still increase. (3 points)二、选择题（每题3分，共27分。每题只有一个正确答案。）1. Melissa buys an iPod for $120 and gets consumer surplus of $80. If the price of an iPod were$90, her consumer surplus would be. If the price were $250, her cons

11、umer surplus would be.A. $110; $-50 B. $110; $0C. $0; $0 D. $0; $-502. Suppose an early freeze sours the apple crops. Then the producer surplus in the market for apples will. The producer surplus in the market for pears will. The consumer surplus in the market for fruits as a whole will. The social

12、surplus in the market for fruits as a whole will. (Hint: Fruits include apples and pears. Apples and pears are substitutes.)A. decrease, increase, decrease, decreaseB. decrease, increase, decrease, increase or decrease (cannot judge)C. decrease, decrease, decrease, decreaseD. decrease, increase, inc

13、rease, decrease3. 离岸外包（Offshore Outsourcing）是某些企业将部分的中间生产交由劳动力成本更为低 廉的国外工人完成。则这一做法将导致这些企业的工人 ，企业的经营者 ，企 业整体上 。同时，由于产品的生产成本 ，购买这些企业产品的消费者将 。（提示：考虑存在进口的劳动力市场。）A. 受益，受损，受损；上升，受损 B. 受益，受损，受益；降低，受益 C. 受损，受益，受损；降低，受益 D. 受损，受益，受益；降低，受益4.学生宿舍中有两人，吸烟者和非吸烟者。学校考虑制定相关规定。第 1 种规定是吸烟者无需经过非吸烟者同意就可以吸烟。第 2 种规定是吸烟者需要经

14、过非吸烟者同意后才能 吸烟。第 3 种规定是对吸烟者罚款 100 元。假定非吸烟者对不吸烟的评价为 110 元（相 对于被吸烟而言）。前两种规定下允许科斯谈判，第三种规定不允许科斯谈判。则对于 吸烟者而言，第 种规定最有利，第 种规定最不利。A. 3，2B. 1，2C. 1，3D. 无法判断5. 远古时代，人类社会从从事采集和狩猎业纷纷转向种植和畜牧业，由此获得了生产率的 极大提高，很好地解决了人口增长带来的生存问题。这被历史学家称为“第一次经济革 命”。对于生产率提高的原因，你认为合乎经济学原理的解释是：A. 种植作物和蓄养家畜比野生动植物具有更高的繁殖能力B. 人类和其他动物相比，天生更善

15、于从事种植和畜牧业而非采集和狩猎业C. 种植和畜牧业很好地解决了采集和狩猎业固有的“共有地悲剧”（Tragedy of Commons） 问题D. 人类对于种植作物和蓄养家畜的供给增加满足了对其需求的增加6. Some states in the U.S. exclude necessities, such as food and clothing, from their sales tax. They also impose a higher tax on other goods to keep their total revenue unchanged. Such exclusion is

16、 most likely to be:A. good for efficiency but bad for equityB. bad for efficiency but good for equityC. good for both efficiency and equityD. bad for both efficiency and equity7. Tim earns income of $60,000 per year and pays $21,000 per year in taxes. Tim paid 20 percent in taxes on the first $30,00

17、0 he earned. What was the marginal tax rate on the second$30,000 he earned?A. 20 percentB. 30 percentC. 50 percentD. 70 percent8. A lump-sum tax is a tax that is the same amount for every person. According to the two objectives of efficiency and equity of tax system, this tax is:A. very efficient bu

18、t very inequitableB. very inefficient and inequitableC. very efficient and equitableD. very inefficient but very equitable9. If a poor family with an annual income of $10,000 has three children in public school and a rich family with an annual income of $100,000 has only one child in public school a

19、nd two children in private school, the benefits principle would suggest that thefamily should pay more in taxes to pay for public education, and the ability-to-pay principle would suggest that thefamily should pay more in taxes to pay for public education.A. poor, richB. poor, poorC. rich, poorD. ri

20、ch, rich三、问答题（共 3 题，49 分）1. Tradable Pollution Permits (10 points)There are three industrial firms in Happy Valley.FirmInitialPollution LevelCost of ReducingPollution by 1 UnitA70 units$20B80 units$25C50 units$10The government wants to reducing pollution to 120 units, so it gives each firm 40 tradab

21、le pollution permits.a. Who sells permits and how many do they sell? Who buys permits and how many do they buy? What is the total cost of pollution reduction in this situation? Use a graph to explain all your answers. What theory are your answers based on? (4 points)We can draw a graph for demand an

22、d supply of pollution rights as below. Each firm will demandpollution rights at his initial pollution level if its price is below its unit cost of reducing pollution. Otherwise it would reduce all its pollutions. The supply is fixed at the amount of permits government issues. (1 points)The figure sh

23、ows that at equilibrium firm B will hold 80 permits, A will hold 40 permits and C will not hold any permits. So C will sell all his permits (40) to B. (1 point)The total cost of pollution reduction is illustrated by the shaded area, which is (150-120)*20+(200-150)*10=$1,100. (1 point)The theory the

24、answers are based on is Coase theorem. It states that people can trade until they reach an outcome maximizing their joint welfare. (1 point)Firm BSupply for pollution rightsDemand for pollum AFirFirm CPrice of pollution25tion rights201080120150200Quantity of pollutionAnother possible way of graphing

25、 is considering the net demand and net supply instead of gross demand and gross supply. Note that each firm has initial endowment of 40 permits. So for example, when the price of permits (or pollution) is less than 25, firm Bs net demand is just 40 permits instead of 80.Firm BFirm BSupply for pollut

26、ion rightsFirm CFirm AFirm CDemand for pollution rightsPrice of pollution2520104070 80120Quantity of pollutionThe equilibrium price is $20. And C will sell all its 40 permits and B will buy those 40 permits. firm A will not buy or sell any permits (or equivalently, firm A buys from itself 0 to 30 pe

27、rmits at price of $20). The answer is the same as we consider the gross demand and supply.b. How much higher would the cost of pollution reduction be if the permits could not be traded? (1 point)If the permits could not be traded, then firm A would have to reduce its pollution by 30 units at a cost

28、of $20 x 30 = $600, firm B would reduce its pollution by 40 units at a cost of $25 x 40 =$1,000, and firm C would reduce its pollution by 10 units at a cost of $10 x 10 = $100. The total cost of pollution reduction would be $1,700, $600 higher than in the case in which the permits could be traded. (

29、1 point)c. Suppose the government gives 120 permits all to firm A. How do your answers in part (a) and(b) change? Explain. (2 points)The equilibrium is still as in part (a). That is, firm B would finally get 80 permits and A would still hold the other 40 permits. So firm A would sell 80 permits to f

30、irm B. (1 point)The total cost of pollution reduction is the same as in part (a), i.e., $1,100, which is $600 (OR$1,400) lower than the case in which permits could not be traded and each holds 40 permits at the beginning (OR just A holds all the permits). (1 point)If you use the net demand-supply an

31、alysis, the graph is as below, but the equilibrium is the same.Supply for pollution rightsFirm BFirm AFirm CDemand for pollution rightsPrice of pollution2520105080120 130Quantity of pollutiond. Suppose government gives each firm 40 tradable pollution permits, but firm B is prohibited from trading pe

32、rmits with any other firm. Who sells permits and how many do they sell? Who buys permits and how many do they buy? What is the total cost of pollution reduction in this situation? Use a graph to explain all your answers. How much higher is the cost of pollution reduction than if the permits could be

33、 traded freely between all three firms? (2 points)If firm B is prohibited from trade, the market for pollution rights is shown as the graph below. Firm A will finally have 70 permits and C will have 10 permits. So Firm C will sell 30 permits to firm A. (1 point)The total cost of pollution reduction

34、of A and C together is the shaded area, which equals to $400. Firm B would have to reduce 40 units of pollution, with a cost of 40*25=$1000. The total cost pollution reduction of all three firms is $400+$1,000=$1,400, which is $300 higher than free trade case. (1 point)Supply for pollution rightsFir

35、m ADemand for pollution rightsFirm CPrice of pollution25201070 80120Quantity of pollutionThe net demand-supply graph is as below. The answer would be the same.Firm AFirm ASupply for pollution rightsFirm CDemand for pollution rightsFirm CPrice of pollution252010304080Quantity of pollutione. If the go

36、vernment instead wants to use a corrective tax on pollution to reduce it to no more than 120 units. What is the smallest tax size the government should set? (1 point)The government should set the size of tax at least at $20 (or slightly less than $20).2.住房限购政策的影响（16 分） 考虑一个买卖住房市场。（1） 画出一个典型的市场供求图形表示

37、该住房市场。（1 分） 如下图。需求供给住房价格 P均衡价格 P*均衡数量 Q*住房数量 Q政府出台政策限制该市场买者可以购买的数量。假定该限制政策使得在任何价格下的 需求量都减少一半（例如，原来所有人最多买两套房，现在都只能买一套房）。（2） 当住房供给弹性较大时，限购政策如何影响市场均衡？这一政策倾向于使得买者总 体上受益还是受损？生产者总体上受益还是受损？社会总福利增加还是减少？画图 仔细说明。（提示：考虑完全供给弹性。）（2 分）为分析简便，考虑一个完全富于弹性的供给。如下图。限购政策使得需求曲线左移，横向移 动原距离的一半。均衡数量从 Q1*下降到 Q2*=(1/2)Q1*。但均衡价

38、格不变：P1*=P2*。（如果 供给弹性不是无穷大但较大，则均衡数量下降较大，但均衡价格下降较小。）（0.5 分） 消费者剩余从面积 ABE1 下降到 ABE2，下降一半。（0.5 分） 生产者剩余不变。（但如果供给弹性不是无穷大，生产者剩余肯定有所下降，因为需求减少。）（0.5 分） 社会总福利下降，此处等于消费者剩余下降。（但如果供给弹性不是无穷大，则社会总福利 下降还包括生产者剩余的下降。）（0.5 分）BA需求E2E1供给住房价格 PP2*=P1*Q2*=(1/2)Q1*Q1*住房数量 Q（3） 当住房供给弹性较小时，这一政策倾向于使得买者总体上受益还是受损？生产者总 体上受益还是受损

39、？社会总福利增加还是减少？画图仔细说明。（提示：考虑供给完 全无弹性。）（3 分）为分析简便，考虑供给完全无弹性。如下图。（0.5 分） 限购政策不改变均衡数量：Q2*=Q1*。但使得均衡价格下降，P2*0。如图。（1 分）SP1*P2*DrDp+DrDp0=Q*p1Q*p2Q*r2Q*r1Q*r1不过，这一政策却未必能使穷人买得起房。考虑富人的需求弹性上升。则价格的下降减少， 有可能高于穷人的最高支付意愿（图中红线）。此时，富人购房量不变，穷人也不变（为零）。（1 分） 在上述第一种情形下，限购对于穷人有利，但未必对于富人不利（富人购买量下降，但同时 价格也下降了）。（0.5 分） 在上述第

40、二种情形下，限购对于穷人无影响。但对于富人有利，理由同第（3）问。（0.5 分）SP1* P2*P2*DrDp+DrDpQ*p2Q*r20=Q*p1=Qp2*Q*r1=Qr2*Q*r1（7） 现在改变限购使得所有人都减少一半需求量的假设。假定限购使得富人的需求量降 为零，但穷人的需求不变。（因为富人拥有的住房数量已经达到了上限，穷人并不想 买两套房）。限购政策必定使穷人买得起房吗？限购政策必定对穷人有利而对富人不 利吗？（提示：考虑供给弹性。） （2 分）当供给无弹性时，如下图。穷人必定买得起房。限购政策必定对穷人有利而对富人不利。（1 分）SP1*P2*DpDrDp+Dr0=Qp1* Q*p

41、2Q*r2=0Q*r1Q*r1=Q*p2当供给完全富于弹性时，如下图，住房市场消失。穷人仍然得不到住房，限购政策对所有人 不利。（1 分）P1*SDpDrDp+Dr0=Qp1*=Qp2*Q*r2=0Q*r10Q*r13. Health Insurance (23 points)Consider how health insurance affects the quantity of healthcare services performed. Suppose that the typical medical procedure has a cost of $c. A typical individual (inverse) demand curve for healthcare services is p=b-a*n, where p is price of each medical procedure, n is the number of procedures an individual demands, b and a are constant. There are N individual