经济学原理曼昆课后答案chapter7

✍ how to define and measure consumer surplus.✍ the link between sellers’ costs of producing a good and the supply curve.✍ how to define and measure producer surplus.✍ that the equilibrium of supply and demand maximizes total surplus in a market. CONTEXT AND PURPOSE:Chapter 7 is the first chapter in a three-chapter sequence on welfare economics and market efficiency. Chapter 7 employs the supply and demand model to develop consumer surplus and producer surplus as a measure of welfare and market efficiency. These concepts are then utilized in Chapters 8 and 9 to determine the winners and losers from taxation and restrictions on international trade.The purpose of Chapter 7 is to develop welfare economics—the study of how the allocation of resources affects economic well-being. Chapters 4 through 6 employed supply and demand in a positive framework, which focused on the question, “What is the equilibrium price and quantity in a market?” This chapter now addresses the normative question, “Is the equilibrium price and quantity in a market the best possible solution to the resource allocation problem, or is it simply the price and quantity that balance supply and demand?” Students will discover that under most circumstances the equilibrium price and quantity is also the one that maximizes welfare.KEY POINTS:? Consumer surplus equals buyers’ willingness to pay for a good minus the amount they actually pay for it, and it measures the benefit buyers get from participating in a market.Consumer surplus can be computed by finding the area below the demand curve and above the price.? Producer surplus equals the amount sellers receive for their goods minus their costs of production, and it measures the benefit sellers get from participating in a market. Producer surplus can be computed by finding the area below the price and above the supply curve.? An allocation of resources that maximizes the sum of consumer and producer surplus is said to be efficient. Policymakers are often concerned with the efficiency, as well as the equality, of economic outcomes.? The equilibrium of supply and demand maximizes the sum of consumer and producer surplus.That is, the invisible hand of the marketplace leads buyers and sellers to allocate resources efficiently.? Markets do not allocate resources efficiently in the presence of market failures such as market power or externalities.CHAPTER OUTLINE:I. Definition of welfare economics: the study of how the allocation of resources affects economic well-being.A. Willingness to Pay1. Definition of willingness to pay: the maximum amount that a buyer will pay for a good.2. Example: You are auctioning a mint-condition recording of Elvis Presley’s first album. Four buyers show up. Their willingness to pay is as follows:for John. Because John is willing to pay more than he has to for the album,he derives some benefit from participating in the market.3. Definition of consumer surplus: the amount a buyer is willing to pay for a good minus the amount the buyer actually pays for it.4. Note that if you had more than one copy of the album, the price in the auction would end up being lower (a little over $70 in the case of two albums) and both John and Paul would gain consumer surplus.B. Using the Demand Curve to Measure Consumer Surplus1. We can use the information on willingness to pay to derive a demand curve for the rare2. . Because the demand curve shows the buyers’ willingness to pay, we can use the demand curve to measure consumer surplus.C. How a Lower Price Raises Consumer Surplusare paying less for the product than before (area A on the graph).b. Because the price is now lower, some new buyers will enter the market and receive consumer surplus on these additional units of output purchased (area B on the graph).D. What Does Consumer Surplus Measure?1. Remember that consumer surplus is the difference between the amount that buyers are willing to pay for a good and the price that they actually pay.2. Thus, it measures the benefit that consumers receive from the good as the buyers themselves perceive it.III. Producer SurplusA. Cost and the Willingness to Sell1. Definition of cost: the value of everything a seller must give up to produce a good .2. Example: You want to hire someone to paint your house. You accept bids for the work from four sellers. Each painter is willing to work if the price you will pay exceeds her opportunity cost. (Note that this opportunity cost thus represents willingness to sell.) The costs are: ALTERNATIVE CLASSROOM EXAMPLE:Review the material on price ceilings from Chapter 6. Redraw the market for two-bedroom apartments in your town. Draw in a price ceiling below the equilibriumprice.Then go through:✍ consumer surplus before the price ceiling is put into place.✍ consumer surplus after the price ceiling is put into place.You will need to take some time to explain the relationship between the producers’ willingness to sell and the cost of producing the good. The relationship between cost and the supply curve is not as apparent as the relationship between the demand curve and willingness to pay. It is important to stress that consumer surplus is measured in monetary terms. Consumer surplus gives us a way to place a monetary cost on inefficient market outcomes (due to government involvement or market failure).except for Grandma. Because Grandma receives more than she would require to paint the house, she derives some benefit from producing in the market.4.Definition of producer surplus: the amount a seller is paid for a good minus the seller’s cost of providing it.5. Note that if you had more than one house to paint, the price in the auction would end up being higher (a little under $800 in the case of two houses) and both Grandma and Georgia would gain producer surplus.B. Using the Supply Curve to Measure Producer Surplus1. We can use the information on cost (willingness to sell) to derive a supply curve for2. marginal seller . Because the supply curve shows the sellers’ cost (willingness to sell), we can use the supply curve to measure producer surplus.are receiving more for the product than before (area C on the graph).b. Because the price is now higher, some new sellers will enter the market and receive producer surplus on these additional units of output sold (area D on the graph).D. Producer surplus is used to measure the economic well-being of producers, much like consumer surplus is used to measure the economic well-being of consumers.ALTERNATIVE CLASSROOM EXAMPLE:Review the material on price floors from Chapter 6. Redraw the market for anagricultural product such as corn. Draw in a price support above the equilibriumprice.Then go through:✍ producer surplus before the price support is put in place.✍ producer surplus after the price support is put in place.Make sure that you discuss the cost of the price support to taxpayers.IV.Market EfficiencyA. The Benevolent Social Planner1. The economic well-being of everyone in society can be measured by total surplus, which is the sum of consumer surplus and producer surplus:Total Surplus = Consumer Surplus + Producer SurplusTotal Surplus = (Value to Buyers – Amount Paid by Buyers) +(Amount Received by Sellers – Cost to Sellers)Because the Amount Paid by Buyers = Amount Received bySellers:2. Definition of efficiency: the property of a resource allocation of maximizing the total surplus received by all members of society .3. Definition of equality: the property of distributing economic prosperity uniformly the members of society .a. Buyers who value the product more than the equilibrium price will purchase the product; those who do not, will not purchase the product. In other words, the free market allocates the supply of a good to the buyers who value it most highly, as measured by their willingness to pay.b. Sellers whose costs are lower than the equilibrium price will produce the product; those whose costs are higher, will not produce the product. In other words, the free market allocates the demand for goods to the sellers who can produce it at the lowest cost.to the marginal buyer is greater than the cost to the marginal seller so total surplus would rise if output increases.b. At any quantity of output greater than the equilibrium quantity, the value of the product to the marginal buyer is less than the cost to the marginal seller so total surplus would rise if output decreases.3. Note that this is one of the reasons that economists believe Principle #6: Markets are usually a good way to organize economic activity.It would be a good idea to remind students that there are circumstances whenthe market process does not lead to the most efficient outcome. Examplesinclude situations such as when a firm (or buyer) has market power over priceor when there are externalities present. These situations will be discussed inlater chapters.Pretty Woman, Chapter 6. Vivien (Julia Roberts) and Edward (Richard Gere)negotiate a price. Afterward, Vivien reveals she would have accepted a lowerprice, while Edward admits he would have paid more. If you have done a goodjob of introducing consumer and producer surplus, you will see the light bulbsgo off above your students’ heads as they watch this clip.C. In the News: Ticket Scalping1. Ticket scalping is an example of how markets work to achieve an efficient outcome.2. This article from The Boston Globe describes economist Chip Case’s experience with ticket scalping.D. Case Study: Should There Be a Market in Organs?1. As a matter of public policy, people are not allowed to sell their organs.a. In essence, this means that there is a price ceiling on organs of $0.b. This has led to a shortage of organs.2. The creation of a market for organs would lead to a more efficient allocation of resources, but critics worry about the equity of a market system for organs.V. Market Efficiency and Market FailureA. To conclude that markets are efficient, we made several assumptions about how markets worked.1. Perfectly competitive markets.2. No externalities.B. When these assumptions do not hold, the market equilibrium may not be efficient.C. When markets fail, public policy can potentially remedy the situation. SOLUTIONS TO TEXT PROBLEMS:Quick Quizzes1. Figure 1 shows the demand curve for turkey. The price of turkey is P1 and the consumer surplus that results from that price is denoted CS. Consumer surplus is the amount a buyer is willing to pay for a good minus the amount the buyer actually pays for it. It measures the benefit to buyers of participating in a market.Figure 1 Figure 22. Figure 2 shows the supply curve for turkey. The price of turkey is P1 and the producer surplus that results from that price is denoted PS. Producer surplus is the amount sellers are paid for a good minus the sellers’ cost of providing it (measured by the supply curve). It measures the benefit to sellers of participating in a market.Figure 33. Figure 3 shows the supply and demand for turkey. The price of turkey is P1, consumer surplus is CS, and producer surplus is PS. Producing more turkeys than the equilibrium quantity would lower total surplus because the value to the marginal buyer would be lower than the cost to the marginal seller on those additional units.Questions for Review1. The price a buyer is willing to pay, consumer surplus, and the demand curve are all closely related. The height of the demand curve represents the willingness to pay of the buyers. Consumer surplus is the area below the demand curve and above the price, which equals the price that each buyer is willing to pay minus the price actually paid.2. Sellers' costs, producer surplus, and the supply curve are all closely related. The height of the supply curve represents the costs of the sellers. Producer surplus is the area below the price and above the supply curve, which equals the price received minus each seller's costs of producing the good.Figure 43. Figure 4 shows producer and consumer surplus in a supply-and-demand diagram.4. An allocation of resources is efficient if it maximizes total surplus, the sum of consumer surplus and producer surplus. But efficiency may not be the only goal of economic policymakers; they may also be concerned about equity the fairness of the distribution of well-being.5. The invisible hand of the marketplace guides the self-interest of buyers and sellers into promoting general economic well-being. Despite decentralized decision making and self-interested decision makers, free markets often lead to an efficient outcome.6. Two types of market failure are market power and externalities. Market power may cause market outcomes to be inefficient because firms may cause price and quantity to differ from the levels they would be under perfect competition, which keeps total surplus from being maximized. Externalities are side effects that are not taken into account by buyers and sellers. As a result, the free market does not maximize total surplus.Problems and Applications1. a. Consumer surplus is equal to willingness to pay minus the price paid. Therefore, Melissa’s willingness to pay must be $200 ($120 + $80).b. Her consumer surplus at a price of $90 would be $200 ? $90 = $110.c. If the price of an iPod was $250, Melissa would not have purchased one because the price is greater than her willingness to pay. Therefore, she would receive no consumer surplus.2. If an early freeze in California sours the lemon crop, the supply curve for lemons shifts to the left, as shown in Figure 5. The result is a rise in the price of lemons and a decline in consumer surplus from A + B + C to just A. So consumer surplus declines by the amount B + C.Figure 5 Figure 6In the market for lemonade, the higher cost of lemons reduces the supply of lemonade, as shown in Figure 6. The result is a rise in the price of lemonade and a decline in consumer surplus from D + E + F to just D, a loss of E + F. Note that an event that affects consumer surplus in one market often has effects on consumer surplus in other markets.3. A rise in the demand for French bread leads to an increase in producer surplus in the market for French bread, as shown in Figure 7. The shift of the demand curve leads to an increased price, which increases producer surplus from area A to area A + B + C.Figure 7The increased quantity of French bread being sold increases the demand for flour, as shown in Figure 8. As a result, the price of flour rises, increasing producer surplus from area Dto D + E + F. Note that an event that affects producer surplus in one market leads to effects on producer surplus in related markets.Figure 84. a.Figure 9b. When the price of a bottle of water is $4, Bert buys two bottles of water. His consumer surplus is shown as area A in the figure. He values his first bottle of water at $7, but pays only $4 for it, so has consumer surplus of $3. He values his second bottle of water at $5, but pays only $4for it, so has consumer surplus of $1. Thus Bert’s total consumer surplus is $3 + $1 = $4, which is the area of A in the figure.c. When the price of a bottle of water falls from $4 to $2, Bert buys three bottles of water, an increase of one. His consumer surplus consists of both areas A and B in the figure, an increase in the amount of area B. He gets consumer surplus of $5 from the first bottle ($7 value minus $2 price), $3 from the second bottle ($5 value minus $2 price), and $1 from the third bottle ($3 value minus $2 price), for a total consumer surplus of $9. Thus consumer surplus rises by $5 (which is the size of area B) when the price of a bottle of water falls from $4 to $2.5. a.Figure 10b. When the price of a bottle of water is $4, Ernie sells two bottles of water. His producer surplus is shown as area A in the figure. He receives $4 for his first bottle of water, but it costs only $1 to produce, so Ernie has producer surplus of $3. He also receives $4 for his second bottle of water, which costs $3 to produce, so he has producer surplus of $1. Thus Ernie’s total producer surplus is $3 + $1 = $4, which is the area of A in the figure.c. When the price of a bottle of water rises from $4 to $6, Ernie sells three bottles of water, an increase of one. His producer surplus consists of both areas A and B in the figure, an increase by the amount of area B. He gets producer surplus of $5 from the first bottle ($6 price minus $1 cost), $3 from the second bottle ($6 price minus $3 cost), and $1 from the third bottle ($6 price minus $5 price), for a total producer surplus of $9. Thus producer surplus rises by $5 (which is the size of area B) when the price of a bottle of water rises from $4 to $6.6. a. From Ernie’s supply schedule and Bert’s demand schedule, the quantityequilibrium quantity of two.b. At a price of $4, consumer surplus is $4 and producer surplus is $4, as shown in Problems 3 and 4 above. Total surplus is $4 + $4 = $8.c. If Ernie produced one less bottle, his producer surplus would decline to $3, as shown in Problem 4 above. If Bert consumed one less bottle, his consumer surplus would decline to $3, as shown in Problem 3 above. So total surplus would decline to $3 + $3 = $6.d. If Ernie produced one additional bottle of water, his cost would be $5, but the price is only $4, so his producer surplus would decline by $1. If Bert consumed one additional bottle of water, his value would be $3, but the price is $4, so his consumer surplus would decline by $1. So total surplus declines by $1 + $1 = $2.7. a. The effect of falling production costs in the market for stereos results in a shift to the right in the supply curve, as shown in Figure 11. As a result, the equilibrium price of stereos declines and the equilibrium quantity increases.Figure 11b. The decline in the price of stereos increases consumer surplus from area A to A + B + C + D, an increase in the amount B + C + D. Prior to the shift in supply, producer surplus was areas B + E (the area above the supply curve and below the price). After the shift in supply, producer surplus is areas E + F + G. So producer surplus changes by the amount F + G – B, which may be positive or negative. The increase in quantity increases producer surplus, while the decline in the price reduces producer surplus. Because consumer surplus rises by B + C + D and producer surplus rises by F + G – B, total surplus rises by C + D + F + G.c. If the supply of stereos is very elastic, then the shift of the supply curve benefits consumers most. To take the most dramatic case, suppose the supply curve were horizontal, as shown in Figure 12. Then there is no producer surplus at all. Consumers capture all the benefits of falling production costs, with consumer surplus rising from area A to area A + B.Figure 128. Figure 13 shows supply and demand curves for haircuts. Supply equals demand at a quantity of three haircuts and a price between $4 and $5. Firms A, C, and D should cut the hair of Ellen, Jerry, and Phil. Oprah’s willingness to pay is too low and firm B’s costs are too high, so they do not participate. The maximum total surplus is the area between the demand and supply curves, which totals $11 ($8 value minus $2 cost for the first haircut, plus $7 value minus $3 cost for the second, plus $5 value minus $4 cost for the third).Figure 139. a. The effect of falling production costs in the market for computers results in a shift to the right in the supply curve, as shown in Figure 14. As a result, the equilibrium price of computers declines and the equilibrium quantity increases. The decline in the price of computers increases consumer surplus from area A to A + B + C + D, an increase in the amount B + C + D.Figure 14 Figure 15Prior to the shift in supply, producer surplus was areas B + E (the area above thesupply curve and below the price). After the shift in supply, producer surplus isareas E + F + G. So producer surplus changes by the amount F + G – B, whichmay be positive or negative. The increase in quantity increases producer surplus,while the decline in the price reduces producer surplus. Because consumer surplusrises by B + C + D and producer surplus rises by F + G – B, total surplus rises byC +D + F + G.b. Because typewriters are substitutes for computers, the decline in the price of computers means that people substitute computers for typewriters, shifting the demand for typewriters to the left, as shown in Figure 15. The result is a decline in both the equilibrium price and equilibrium quantity of typewriters. Consumer surplus in the typewriter market changes from area A + B to A + C, a net change of C – B. Producer surplus changes from area C + D + E to area E, a net loss of C + D. Typewriter producers are sad about technological advances in computers because their producer surplus declines.c. Because software and computers are complements, the decline in the price and increase in the quantity of computers means that the demand for software increases, shifting the demand for software to the right, as shown in Figure 16. The result is an increase in both the price and quantity of software. Consumer surplus in the software market changes from B + C to A + B, anet change of A – C. Producer surplus changes from E to C + D + E, an increase of C + D, so software producers should be happy about the technological progress in computers.Figure 16d. Yes, this analysis helps explain why Bill Gates is one the world’s richest people, because his company produces a lot of software that is a complement with computers and there has been tremendous technological advance in computers.10. a. With Provider A, the cost of an extra minute is $0. With Provider B, the cost of anextra minute is $1.b. With Provider A, my friend will purchase 150 minutes [= 150 – (50)(0)]. WithProvider B, my friend would purchase 100 minutes [= 150 – (50)(1)].c. With Provider A, he would pay $120. The cost would be $100 with Provider B.Figure 17d. Figure 17 shows the friend’s demand. With Provider A, he buys 150 minutes andhis consumer surplus is equal to (1/2)(3)(150) – 120 = 105. With Provider B, hisconsumer surplus is equal to (1/2)(2)(100) = 100.e. I would recommend Provider A because he receives greater consumer surplus.11. a. Figure 18 illustrates the demand for medical care. If each procedure has a price of $100, quantity demanded will be Q1 procedures.Figure 18b. If consumers pay only $20 per procedure, the quantity demanded will be Q2 procedures. Because the cost to society is $100, the number of procedures performed is too large to maximize total surplus. The quantity that maximizes total surplus is Q1 procedures, which is less than Q2.c. The use of medical care is excessive in the sense that consumers get procedures whose value is less than the cost of producing them. As a result, the economy’s total surplus is reduced.d. To prevent this excessive use, the consumer must bear the marginal cost of the procedure. But this would require eliminating insurance. Another possibility would be that the insurance company, which pays most of the marginal cost of the procedure ($80, in this case) could decide whether the procedure should be performed. But the insurance company does not get the benefits of the procedure, so its decisions may not reflect the value to the consumer.。

曼昆经济学原理（第四版）课后习题中文答案（7）[小编整理]第一篇：曼昆经济学原理(第四版)课后习题中文答案(7)图 26－4 政府借款对可贷资金市场的影响由于可贷资金的供给弹性衡量可贷资金供给量对利率变化的反应程度，所以它反映在可贷资金供给曲线的形状上。

当可贷资供给弹性大时，即可贷资金供给曲线平缓，在这种情况下，当市场利率上升时，可贷资金供给量会大量增加，尤其是私人储蓄，因为公共储蓄由政府收入和政府支出决定，所以公共储蓄不变，国民储蓄会大量增加。

(见图a)当可贷资金供给弹性小时，既可贷资金供给曲线陡峭，在这种情况下，当市场利率大幅度上升时，可贷资金供给没有增加多少，尤其是私人储蓄没有大量增加，因为公共储蓄不受利率的影响，因此，国民储蓄没有增加多少。

(见图 b)D．可贷资金需求弹性如何影响这些变动的大小? 答：当可贷资金的需求弹性大时，政府借款增加200 亿美元引起的利率上升会挤出大量的投资。

当可贷资金的需求弹性小时，政府借款的增加只会减少小部分私人投资。

(a)可贷资金需求弹性大(b)可贷资金需求弹性小图 26－5 可贷资金需求弹性对可贷资金市场的影响E．假设家庭相信，政府现在借款越多意味着未来为了偿还政府债务而必须征收的税收越高。

这种信念对私人储蓄和现在可贷资金的供给有什么影响？这种信念加强还是减弱了你在 A 与 B 中所讨论的影响? 答：为了偿还现在积累的债务，政府将要在未来增加税收，这种信念会使家庭认为减税并没有减少家庭的整体税单，它仅仅是延期而已。

因此家庭会把所有的减税储蓄起来，而不是支出其中一部分，因而会使私人储蓄增加。

由于私人储蓄增加量完全等于公共储蓄减少量，作为公共和私人储蓄之和的国民储蓄并没有变，因此可贷资金的供给没有变。

这种信念减弱了 A 与 B 中所讨论的影响。

9．过去的十年间，新电脑技术使企业大大减少了它们每销售一美元所持有的存货量。

说明这种变化对可贷资金市场的影响。

(提示：用于存货的支出是一种投资。

曼昆《经济学原理（微观经济学分册）》（第7版）课后习题详解第1章经济学十大原理一、概念题1．稀缺性（scarcity）答：经济学研究的问题和经济物品都是以稀缺性为前提的。

稀缺性指在给定的时间内，相对于人的需求而言，经济资源的供给总是不足的，也就是资源的有用性与有限性。

人类消费各种物品的欲望是无限的，满足这种欲望的物品，有的可以不付出任何代价而随意取得，称之为自由物品，如阳光和空气；但绝大多数物品是不能自由取用的，因为世界上的资源（包括物质资源和人力资源）是有限的，这种有限的、为获取它必须付出某种代价的物品，称为“经济物品”。

正因为稀缺性的客观存在，地球上就存在着资源的有限性和人类的欲望与需求的无限性之间的矛盾。

经济学的一个重要研究任务就是：“研究人们如何进行抉择，以便使用稀缺的或有限的生产性资源（土地、劳动、资本品如机器、技术知识）来生产各种商品，并把它们分配给不同的社会成员进行消费。

”也就是从经济学角度来研究使用有限的资源来生产什么、如何生产和为谁生产的问题。

2．经济学（economics）答：经济学是研究如何将稀缺的资源有效地配置给相互竞争的用途，以使人类的欲望得到最大限度满足的科学。

时下经常见诸国内报刊文献的“现代西方经济学”一词，大多也都在这个意义上使用。

自从凯恩斯的名著《就业、利息和货币通论》于1936年发表之后，西方经济学界对经济学的研究便分为两个部分：微观经济学与宏观经济学。

微观经济学是以单个经济主体（作为消费者的单个家庭或个人，作为生产者的单个厂商或企业，以及单个产品或生产要素市场）为研究对象，研究单个经济主体面对既定的资源约束时如何进行选择的科学。

宏观经济学则以整个国民经济为研究对象，主要着眼于对经济总量的研究。

3．效率（efficiency）答：效率指人们在实践活动中的产出与投入之比值，或者是效益与成本之比值，如果比值大，效率就高；反之，比值小，效率就低。

效率与产出或者收益的大小成正比，而与成本或投入成反比，也就是说，如果想提高效率，必须降低成本或投入，提高收益或产出。

二十三章1下列每种交易会影响CDP的哪一部分(如果有影响的话)并解释之。

A．家庭购买了一台新冰箱。

答：家庭购买了一台新冰箱会增加GDP中的消费(C)部分，因为家庭用于家用电器的支出计算在消费的耐用品类中。

B．杰妮姑妈买了一所新房子。

答：杰妮姑妈买了一所新房子会增加GDP中的投资(1)部分，因为家庭住宅能长期供人居住，提供服务。

它比一般耐用消费品的使用寿命更长，因此把住宅房屋的投资计算在投资中。

C.福特汽车公司由其存货中出售了一部雷鸟牌汽车。

答：福利汽车公司由其存货中出售了一部雷鸟牌汽车会减少现期GDP中的投资，因为销售中间物品存货时，企业的存货投资是负的，因而减少了当期的GDP。

C．你买了一个比萨饼。

答：我买了一个比萨饼会增加GDP中的消费(C)，因为我用于购买食品的支出计算在消费的非耐用品类中。

D．加利福尼亚重新铺设了101号高速公路。

答：加利福尼亚重新铺设了101号高速公路增加了GDP中的政府购买(G)，因为修建高速公路是政府的行为。

E．你的父母购买了一瓶法国红酒。

答：我的父母购买了一瓶法国红酒会减少GDP中的净出口(NX)，因为法国红酒是进口食品，它的购买增加了美国的进口。

F．本田公司扩大其在俄亥俄州马利斯维尔的工厂。

答：本田公司扩大其在俄亥俄州马利斯维尔的工厂增加了GDP中的净出口(NX)，因为本田公司是一家日本企业，它在美国的投资减少了美国对日本本田汽车的进口，使NX增加2．GDP组成部分中的“政府购买”并不包括用于社会保障这类转移支付的支出。

想想GDP 的定义，解释为什么转移支付不包括在政府购买内答：因为转移支付并不是要交换现在生产的物品或劳务，从宏观经济的角度看，转移支付就像税收和回扣一样。

转移支付和税收一样改变了家庭收入，但并没有反映经济的生产。

由于GDP是要衡量在某一既定时期一个国家从物品与劳务的生产中得到的收入，所以，不把转移支付包括在政府购买内。

6．考虑以下美国GDP的数据：A．1996年到1997年间名义收入增长率是多少(注意：增长率是一个时期到下一个时期百分比的变动。

二十三章1下列每种交易会影响CDP的哪一部分(如果有影响的话)并解释之。

A．家庭购买了一台新冰箱。

答：家庭购买了一台新冰箱会增加GDP中的消费(C)部分，因为家庭用于家用电器的支出计算在消费的耐用品类中。

B．杰妮姑妈买了一所新房子。

答：杰妮姑妈买了一所新房子会增加GDP中的投资(1)部分，因为家庭住宅能长期供人居住，提供服务。

它比一般耐用消费品的使用寿命更长，因此把住宅房屋的投资计算在投资中。

C.福特汽车公司由其存货中出售了一部雷鸟牌汽车。

答：福利汽车公司由其存货中出售了一部雷鸟牌汽车会减少现期GDP中的投资，因为销售中间物品存货时，企业的存货投资是负的，因而减少了当期的GDP。

C．你买了一个比萨饼。

答：我买了一个比萨饼会增加GDP中的消费(C)，因为我用于购买食品的支出计算在消费的非耐用品类中。

D．加利福尼亚重新铺设了101号高速公路。

答：加利福尼亚重新铺设了101号高速公路增加了GDP中的政府购买(G)，因为修建高速公路是政府的行为。

E．你的父母购买了一瓶法国红酒。

答：我的父母购买了一瓶法国红酒会减少GDP中的净出口(NX)，因为法国红酒是进口食品，它的购买增加了美国的进口。

F．本田公司扩大其在俄亥俄州马利斯维尔的工厂。

答：本田公司扩大其在俄亥俄州马利斯维尔的工厂增加了GDP中的净出口(NX)，因为本田公司是一家日本企业，它在美国的投资减少了美国对日本本田汽车的进口，使NX增加2．GDP组成部分中的“政府购买”并不包括用于社会保障这类转移支付的支出。

想想GDP 的定义，解释为什么转移支付不包括在政府购买内答：因为转移支付并不是要交换现在生产的物品或劳务，从宏观经济的角度看，转移支付就像税收和回扣一样。

转移支付和税收一样改变了家庭收入，但并没有反映经济的生产。

由于GDP是要衡量在某一既定时期一个国家从物品与劳务的生产中得到的收入，所以，不把转移支付包括在政府购买内。

6．考虑以下美国GDP的数据：A．1996年到1997年间名义收入增长率是多少(注意：增长率是一个时期到下一个时期百分比的变动。

23章答案一、概念题1.微观经济学（microeconomics）答：微观经济学指研究家庭和企业如何做出决策，以及他们如何在市场上相互交易的经济学。

微观经济学以市场经济中的单个消费者（或称家户、家庭）和生产者（或称厂商、企业）为研究对象，通过分析他们的消费决策或生产决策，来说明消费品和生产要素的价格的决定及其变动，进而说明稀缺性的资源如何得到最有效的配置。

微观经济学的理论目的是为了论证亚当·斯密“看不见的手”原理，这只“看不见的手”就是价格机制。

因此，微观经济学又被称为价格理论。

微观经济学主要解决的问题可以概括为：生产什么、生产多少、如何生产、为谁生产。

其基本假设为：（1）经济行为个体是进行自由的、分散化决策的理性经济人，即消费者追求自身效用的最大化，生产者追求自身利润的最大化。

（2）完全竞争和完全信息。

微观经济学从这两个基本假定出发对上述问题的解决就构成了它的主要内容，具体地，它包括：① 供求规律；② 消费者行为理论，它构成消费品价格决定的需求方面；③ 生产者行为理论或厂商理论，它构成消费品价格决定的供给方面；④ 生产要素的价格决定理论或分配理论；⑤ 一般均衡理论；⑥ 福利经济学；⑦ 市场失灵和微观经济政策。

2.宏观经济学（macroeconomics）答：宏观经济学是与“微观经济学”相对而言的，指研究整体经济现象，包括通货膨胀、失业和经济增长的经济学。

宏观经济学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、国际收支与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。

具体来说，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。

Problems and Applications1.If an early freeze in California sours the lemon crop, the supply curve for lemons shiftsto the left, as shown in Figure 7-5.The result is a rise in the price of lemons and adecline in consumer surplus from A + B + C to just A. So consumer surplus declines by the amount B + C.Figure 7-5In the market for lemonade, the higher cost of lemons reduces the supply of lemonade,as shown in Figure 7-6.The result is a rise in the price of lemonade and a decline inconsumer surplus from D + E + F to just D, a loss of E + F. Note that an event that affectsconsumer surplus in one market often has effects on consumer surplus in other markets.Figure 7-62. A rise in the demand for French bread leads to an increase in producer surplus in themarket for French bread, as shown in Figure 7-7.The shift of the demand curve leads to an increased price, which increases producer surplus from area A to area A + B + C.Figure 7-7The increased quantity of French bread being sold increases the demand for flour, asshown in Figure 7-8.As a result, the price of flour rises, increasing producer surplusfrom area D to D + E + F. Note that an event that affects producer surplus in onemarket leads to effects on producer surplus in related markets.Figure 7-83. a.Bert’ s demand schedule is:Price Quantity DemandedMore than $7 0$5 to $7 1$3 to $5 2$1 to $3 3$1 or less 4Bert’ s demand curve is shown in Figure 7 -9.Figure 7-9b.When the price of a bottle of water is $4, Bert buys two bottles of water.Hisconsumer surplus is shown as area A in the figure.He values his first bottle ofwater at $7, but pays only $4 for it, so has consumer surplus of $3.He valueshis second bottle of water at $5, but pays only $4 for it, so has consumersurplus of $1.Thus Bert’ s total consumer surplus is $3 + $1 = $4, which isthe area of A in the figure.c.When the price of a bottle of water falls from $4 to $2, Bert buys three bottlesof water, an increase of one. His consumer surplus consists of both areas Aand B in the figure, an increase in the amount of area B. He gets consumersurplus of $5 from the first bottle ($7 value minus $2 price), $3 from thesecond bottle ($5 value minus $2 price), and $1 from the third bottle ($3 valueminus $2 price), for a total consumer surplus of $9. Thus consumer surplusrises by $5 (which is the size of area B) when the price of a bottle of water fallsfrom $4 to $2.4. a. Ernie ’ s supply schedule for water is:Price Quantity SuppliedMore than $7 4$5 to $7 3$3 to $5 2$1 to $3 1Less than $1 0Ernie’ s supply curve is shown in Figure 7 -10.Figure 7-10b.When the price of a bottle of water is $4, Ernie sells two bottles of water.Hisproducer surplus is shown as area A in the figure.He receives $4 for his firstbottle of water, but it costs only $1 to produce, so Ernie has producer surplusof $3.He also receives $4 for his second bottle of water, which costs $3 toproduce, so he has producer surplus of$1. Thus Ernie’ s total producersurplus is $3 + $1 = $4, which is the area of A in the figure.c.When the price of a bottle of water rises from $4 to $6, Ernie sells three bottlesof water, an increase of one.His producer surplus consists of both areas Aand B in the figure, an increase by the amount of area B.He gets producersurplus of $5 from the first bottle ($6 price minus $1 cost), $3 from the secondbottle ($6 price minus $3 cost), and $1 from the third bottle ($6 price minus $5price), for a total producer surplus of $9.Thus producer surplus rises by $5(which is the size of area B) when the price of a bottle of water rises from $4to $6.5. a. From Ernie ’ s supply schedule and Bert ’ s demand schedule, the quantitydemanded and supplied are:Price Quantity Supplied Quantity Demanded$ 2 1 34 2 26 3 1Only a price of $4 brings supply and demand into equilibrium, withan equilibrium quantity of 2.b.At a price of $4, consumer surplus is $4 and producer surplus is $4, as shownin problems 3 and 4.Total surplus is $4 + $4 = $8.c.If Ernie produced one fewer bottle, his producer surplus would decline to $3,as shown in problem 4.If Bert consumed one fewer bottle, his consumersurplus would decline to $3, as shown in problem 3. So total surplus would declineto $3 + $3 = $6.d.If Ernie produced one additional bottle of water, his cost would be $5, but theprice is only $4, so his producer surplus would decline by $1.If Bertconsumed one additional bottle of water, his value would be $3, but the priceis $4, so his consumer surplus would decline by $1.So total surplus declinesby $1 + $1 = $2.6. a.The effect of falling production costs in the market for stereos results in a shiftto the right in the supply curve, as shown in Figure 7-11.As a result, theequilibrium price of stereos declines and the equilibrium quantity increases.b.The decline in the price of stereos increases consumer surplus from area A to A+ B + C + D, an increase in the amount B + C + D.Prior to the shift in supply,producer surplus was areas B + E (the area above the supply curve and belowthe price).After the shift in supply, producer surplus is areas E + F + G.Soproducer surplus changes by the amount F + G - B, which may be positive ornegative.The increase in quantity increases producer surplus, while thedecline in the price reduces producer surplus.Since consumer surplus risesby B + C + D and producer surplus rises by F + G - B, total surplus rises by C+ D+F+G.c.If the supply of stereos is very elastic, then the shift of the supply curvebenefits consumers most.To take the most dramatic case, suppose thesupply curve were horizontal, as shown in Figure 7-12.Then there is noproducer surplus at all.Consumers capture all the benefits of fallingproduction costs, with consumer surplus rising from area A to area A + B.Figure 7-11Figure 7-127. Figure 7-13 shows supply and demand curves for haircuts. Supply equals demand ata quantity of three haircuts and a price between $4 and $5. Firms A, C, and D shouldcut the hair of Sally Jessy, Jerry, and Montel. Oprah ’ s willingness to pay is too low and firm B ’ s costs are too high, so they do not participate. The maximum total surplus isthe area between the demand and supply curves, which totals $11 ($8 value minus$2 cost for the first haircut, plus $7 value minus $3 cost for the second, plus $5 valueminus $4 cost for the third).Figure 7-138. a.The effect of falling production costs in the market for computers results in ashift to the right in the supply curve, as shown in Figure 7-14.As a result, theequilibrium price of computers declines and the equilibrium quantity increases.The decline in the price of computers increases consumer surplus from area Ato A + B + C + D, an increase in the amount B + C + D.Figure 7-14Prior to the shift in supply, producer surplus was areas B + E (the area abovethe supply curve and below the price).After the shift in supply, producersurplus is areas E + F + G.So producer surplus changes by the amount F + G- B, which may be positive or negative.The increase in quantity increasesproducer surplus, while the decline in the price reduces producer surplus. Sinceconsumer surplus rises by B + C + D and producer surplus rises by F + G - B,total surplus rises by C + D + F + G.——Figure 7-15b.Since adding machines are substitutes for computers, the decline in the priceof computers means that people substitute computers for adding machines,shifting the demand for adding machines to the left, as shown in Figure 7-15.The result is a decline in both the equilibrium price and equilibrium quantity ofadding machines.Consumer surplus in the adding-machine market changesfrom area A + B to A + C, a net gain of C - B.Producer surplus changes fromarea C + D + E to area E, a net loss of C + D.Adding machine producers aresad about technological advance in computers because their producersurplus declines.c.Since software and computers are complements, the decline in the price andincrease in the quantity of computers means that people’ s demand forsoftware increases, shifting the demand for software to the right, as shown inFigure 7-16. The result is an increase in both the price and quantity of software.Consumer surplus in the software market changes from B + C to A+B, a net increase of A - C. Producer surplus changes from E to C + D + E, anincrease of C + D, so software producers should be happy about the technologicalprogress in computers.d.Yes, this analysis helps explain why Bill Gates is one the world’ s richest msince his company produces a lot of software that’ s a complement withcomputers and there has been tremendous technological advance incomputers.——Figure 7-169. a. Figure 7-17 illustrates the demand for medical care. If each procedure has aprice of $100, quantity demanded will be Q 1 procedures.Figure 7-17b.If consumers pay only $20 per procedure, the quantity demanded will be Q 2procedures.Since the cost to society is $100, the number of proceduresperformed is too large to maximize total surplus.The quantity thatmaximizes total surplus is Q 1 procedures, which is less than Q2.c.The use of medical care is excessive in the sense that consumers getprocedures whose value is less than the cost of producing them.As a result,——the economy’ s total surplus is reduced.d.To prevent this excessive use, the consumer must bear the marginal cost ofthe procedure.But this would require eliminating insurance.Anotherpossibility would be that the insurance company, which pays most of themarginal cost of the procedure ($80, in this case) could decide whether theprocedure should be performed.But the insurance company doesn’ t get thebenefits of the procedure, so its decisions may not reflect the value to theconsumer.10. a. Figure 7-18 illustrates the effect of the drought. The supply curve shifts tothe left, leading to a rise in the equilibrium price from P 1 to P 2 and a decline inthe equilibrium quantity from Q 1 to Q 2 .Figure 7-18b.If the price of water is not allowed to change, there will be an excess demandfor water, with the shortage shown on the figure as the difference between Q 1and Q 3 .c.The system for allocating water is inefficient because it no longer allocateswater to those who value it most highly.Some people who value water atmore than its cost of production will be unable to obtain it, so societysurplus isn’ t maximized.The allocation system seems unfair as well.Water is allocated simply on pastusage, rewarding past wastefulness.If a family’ s demand for water increases,——say because of an increase in family size, the policy doesn ’ t allow them to obtain more water. Poor families, who probably used water mostly fornecessary uses like drinking, would suffer more than wealthier families whowould have to cut back only on luxury uses of water like operating backyardfountains and pools. However, the policy also keeps the price of water lower,which benefits poor families, since otherwise more of their family budgetwould have to go for water.d. If the city allowed the price of water to rise to its equilibrium price P 2 , theallocation would be more efficient. Quantity supplied would equal quantitydemanded and there would be no shortage. Total surplus would bemaximized.Whether the market allocation would be more or less fair than theproportionate reduction in water under the old policy is difficult to say, but it islikely to be more fair. Notice that the quantity supplied would be higher (Q 2)in this case than under the water restrictions (Q 3 ), so there ’ s less reduction inwater usage. To make the market solution even more fair, the governmentcould provide increased tax relief or welfare payments for poor families whosuffer from paying the higher water prices.。

1下列每种交易会影响CDP的哪一部分(如果有影响的话)?并解释之。

A．家庭购买了一台新冰箱。

答：家庭购买了一台新冰箱会增加GDP中的消费(C)部分，因为家庭用于家用电器的支出计算在消费的耐用品类中。

B．杰妮姑妈买了一所新房子。

答：杰妮姑妈买了一所新房子会增加GDP中的投资(1)部分，因为家庭住宅能长期供人居住，提供服务。

它比一般耐用消费品的使用寿命更长，因此把住宅房屋的投资计算在投资中。

C.福特汽车公司由其存货中出售了一部雷鸟牌汽车。

答：福利汽车公司由其存货中出售了一部雷鸟牌汽车会减少现期GDP中的投资，因为销售中间物品存货时，企业的存货投资是负的，因而减少了当期的GDP。

C．你买了一个比萨饼。

答：我买了一个比萨饼会增加GDP中的消费(C)，因为我用于购买食品的支出计算在消费的非耐用品类中。

D．加利福尼亚重新铺设了101号高速公路。

答：加利福尼亚重新铺设了101号高速公路增加了GDP中的政府购买(G)，因为修建高速公路是政府的行为。

E．你的父母购买了一瓶xx红酒。

答：我的父母购买了一瓶法国红酒会减少GDP中的净出口(NX)，因为法国红酒是进口食品，它的购买增加了美国的进口。

F．本田公司扩大其在俄亥俄州马利斯维尔的工厂。

答：本田公司扩大其在俄亥俄州马利斯维尔的工厂增加了GDP中的净出口(NX)，因为本田公司是一家日本企业，它在美国的投资减少了美国对日本本田汽车的进口，使NX增加2．GDP组成部分中的“政府购买”并不包括用于社会保障这类转移支付的支出。

想想GDP的定义，解释为什么转移支付不包括在政府购买内?答：因为转移支付并不是要交换现在生产的物品或劳务，从宏观经济的角度看，转移支付就像税收和回扣一样。

转移支付和税收一样改变了家庭收入，但并没有反映经济的生产。

由于GDP是要衡量在某一既定时期一个国家从物品与劳务的生产中得到的收入，所以，不把转移支付包括在政府购买内。

6．考虑以下xxGDP的数据：A．1996年到1997年间名义收入增长率是多少?(注意：增长率是一个时期到下一个时期百分比的变动。

复习题1．解释买者的支付意愿、消费者剩余和需求曲线如何相关。

答：需求曲线反映了买者的支付意愿。

在任何一种数量时，需求曲线给出的价格表示边际买者的支付意愿。

需求曲线以下和价格以上的总面积是一种物品或劳务市场上所有买者消费者剩余的总和。

2．解释卖者的成本、生产者剩余和供给曲线如何相关。

36答：供给曲线的高度与卖者的成本相关。

在任何一种数量时，供给曲线给出的价格表示边际卖者的成本。

价格之下和供给曲线以上的面积衡量市场的生产者剩余。

3．在供求图中，标出市场均衡时的生产者剩余和消费者剩余。

答：APE 的面积代表消费者剩余；PBE 的面积代表生产者剩余。

图7－1 供求图4．什么是效率?它是经济决策者的唯一目标吗?答：效率是指资源配置使社会所有成员得到的总剩余最大化的性质。

除了效率外，经济决策者还应该关心平等。

实际上，市场交易的好处很像在市场参与者之间分割一块蛋糕，经济决策者不仅要关心如何将经济蛋糕做大，即效率；还要考虑如何在市场参与者之间分这块蛋糕，这就涉及公平问题。

5．看不见的手有什么作用?答：每一个市场参与者都会尽力追求自己的利益，看不见的手指引他们在相互竞争中达到一个并非他们本意想要达到的目的，这就是市场均衡点。

在均衡点上，消费者剩余和生产者剩余总和最大化，整个社会福利达到最大。

6．说出两种市场失灵的名称。

解释为什么每一种都可能使市场结果无效率。

答：市场失灵包括市场势力和外部性。

如果某一市场上存在市场势力，即只有极少部分(可能是一个)买者或卖者可以控制市场价格，他们就会使价格趋向于对他们这一小部分人有益的水平。

于是，市场价格和数量背离供求平衡，社会福利达不到最大，市场失去效率。

外部性是某些市场参与者的行为对旁观者福利的影响。

它使市场福利还要取决于买者评价和卖者成本之外的其他因素。

由于买者和卖者在决定消费和生产时并没有考虑这种负作用。

所以，从整个社会角度来看，市场均衡可能是无效率的。

问题与应用1．Melissa用120美元购买了一个iPod，并得到了80美元的消费者剩余。

第七章 消费者、生产者与市场效率复习题：1、解释买者的支付意愿、消费者剩余和需求曲线如何相关。

答：需求曲线反映了买者的支付意愿。

在任何一种数量时，需求曲线给出的价格表示边际买者的支付意愿。

需求曲线以下和价格以上的总面积是一种物品或劳务市场上所有买者消费者剩余的总和。

2、解释卖者的成本、生产者剩余和供给曲线如何相关。

答：供给曲线的高度与卖者的成本相关。

在任何一种数量时，供给曲线给出的价格表示边际卖者的成本。

供给曲线以上和价格以下的总面积衡量市场的生产者剩余。

3、在供求图中，说明市场均衡时的生产者和消费者剩余。

答：4、什么是效率？它是经济决策者的唯一目标吗？答：效率是指资源配置使社会所有成员得到的总剩余最大化的性质。

价格均衡价格数量 APE 的面积代表消费者剩余；PBE 的面积代表生产者剩余。

除了效率外，经济决策者还应该关心平等。

实际上，市场交易的好处很像在市场参与者之间分割一块蛋糕，经济决策者不仅要关心如何奖经济蛋糕做大，即效率；还要考虑如何在市场参与者之间分割这块蛋糕，这就涉及公平问题。

5、看不见的手有什么作用？答：每一个市场参与者都会尽力追求自己的利益，看不见的手指引他们在相互竞争中达到一个并非他们本意想要达到的目的，这就是市场均衡点。

在均衡点上，消费者剩余和生产者剩余总和最大化，整个社会福利达到最大。

6、说出两种市场失灵的名字。

解释为什么每一种都可能使市场结果无效率。

答：市场失灵包括市场势力和外部性。

如果某一市场上存在市场势力，即只有极少部分（可能是一个）买者或卖者可以控制的市场价格，他们就会使价格倾向于对他们这一小部分人有益的水平。

于是，市场价格和数量背离供求平衡，社会福利达不到最大，市场失去效率。

外部性是某些市场参与者的行为对旁观者福利的影响。

它使市场福利还要取决于买者评价和卖者成本之外的其他因素。

由于买者和卖者在决定消费和生产时并没有考虑这种负作用。

所有，从整个社会角度来看，市场均衡可能是无效率的。

曼昆《经济学原理》（第五版）习题解答目录第一章经济学十大原理 (1)第二章像经济学家一样思考 (7)第三章相互依存性与贸易的好处 (14)第四章供给与需求的市场力量 (22)第五章弹性及其应用 (31)第六章供给、需求与政府政策 (41)第七章消费者、生产者与市场效率 (50)第八章应用：赋税的代价 (58)第九章应用：国际贸易 (65)第十章外部性 (75)第十一章公共物品和公共资源 (84)第十二章税制的设计 (91)第十三章生产成本 (99)第十四章竞争市场上的企业 (109)第十五章垄断 (121)第十六章垄断竞争 (135)第十七章寡头 (143)第十八章生产要素市场 (153)第十九章收入与歧视 (162)第二十章收入不平等与贫困 (169)第二十一章消费者选择理论 (177)第二十二章微观经济学前沿 (187)第二十三章一国收入的衡量 (195)第二十四章生活费用的衡量 (204)第二十五章生产与增长 (210)第二十六章储蓄、投资和金融体系 (214)第二十七章基本金融工具 (221)第二十八章失业 (226)第一篇导言第一章经济学十大原理复习题1．列举三个你在生活中面临的重要权衡取舍的例子。

答：①大学毕业后，面临着是否继续深造的选择，选择继续上学攻读研究生学位，就意味着在今后三年中放弃参加工作、赚工资和积累社会经验的机会；②在学习内容上也面临着很重要的权衡取舍，如果学习《经济学》，就要减少学习英语或其他专业课的时间；③对于不多的生活费的分配同样面临权衡取舍，要多买书，就要减少在吃饭、买衣服等其他方面的开支。

2．看一场电影的机会成本是什么?答：看一场电影的机会成本是在看电影的时间里做其他事情所能获得的最大收益，例如：看书、打零工。

3．水是生活必需的。

一杯水的边际利益是大还是小呢?答：这要看这杯水是在什么样的情况下喝，如果这是一个人五分钟内喝下的第五杯水，那么他的边际利益很小，有可能为负；如果这是一个极度干渴的人喝下的第一杯水，那么他的边际利益将会极大。

WHAT’S NEW IN THE SIXTH EDITION:There are no major changes to this chapter.LEARNING OBJECTIVES:By the end of this chapter, students should understand:➢ the link between buyers’ willingness to pay for a good and the demand curve.➢ how to define and measure consumer surplus.➢ the link between sellers’ costs of producing a good and the supply curve.➢ how to define and measure producer surplus.➢ that the equilibrium of supply and demand maximizes total surplus in a market.CONTEXT AND PURPOSE:Chapter 7 is the first chapter in a three-chapter sequence on welfare economics and market efficiency. Chapter 7 employs the supply and demand model to develop consumer surplus and producer surplus as a measure of welfare and market efficiency. These concepts are then utilized in Chapters 8 and 9 to determine the winners and losers from taxation and restrictions on international trade.The purpose of Chapter 7 is to develop welfare economics —the study of how the allocation ofresources affects economic well-being. Chapters 4 through 6 employed supply and demand in a positive framework, which focused on the question, “What is the equilibrium price and quantity in a market?” This chapter now addresses the normative question, “Is the equ ilibrium price and quantity in a market the best possible solution to the resource allocation problem, or is it simply the price and quantity thatbalance supply and demand?” Students will discover that under most circumstances the equilibrium price and quantity is also the one that maximizes welfare.7CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETSKEY POINTS:• Consumer surplus equals buyers’ willingness to pay for a good minus the amount they actually pay for it, and it measures the benefit buyers get from participating in a market. Consumer surplus can be computed by finding the area below the demand curve and above the price.• Producer surplus equals the amount sellers receive for their goods minus their costs of production, and it measures the benefit sellers get from participating in a market. Producer surplus can be computed by finding the area below the price and above the supply curve.•An allocation of resources that maximizes the sum of consumer and producer surplus is said to be efficient. Policymakers are often concerned with the efficiency, as well as the equality, of economic outcomes.• The equilibrium of supply and demand maximizes the sum of consumer and producer surplus. That is,the invisible hand of the marketplace leads buyers and sellers to allocate resources efficiently.• Markets do not allocate resources efficiently in the presence of market failures such as market poweror externalities.CHAPTER OUTLINE:I. Definition of welfare economics: the study of how the allocation of resources affectseconomic well-being.II. Consumer SurplusA. Willingness to Pay1. Definition of willingness to pay: the maximum amount that a buyer will pay for agood.2. Example: You are auctioning a mint-condition recording of Elvis Presley’s first album. Fourbuyers show up. Their willingness to pay is as follows:If the bidding goes to slightly higher than $80, all buyers drop out except forJohn. Because John is willing to pay more than he has to for the album, hederives some benefit from participating in the market.3. Definition of consumer surplus: the amount a buyer is willing to pay for a goodminus the amount the buyer actually pays for it.4. Note that if you had more than one copy of the album, the price in the auction would end upbeing lower (a little over $70 in the case of two albums) and both John and Paul would gain consumer surplus.B. Using the Demand Curve to Measure Consumer Surplus1. We can use the information on willingness to pay to derive a demand curve for the rare ElvisPresley album.PriceBuyersQuantity DemandedMore than $100 None 0 $80 to $100 John1 $70 to $80 John, Paul2 $50 to $70 John, Paul, George3 $50 or lessJohn, Paul, George, Ringo42. At any given quantity, the price given by the demand curve reflects the willingness to pay ofthe marginal buyer . Because the demand curve shows the buyers’ willingness to pay, we can use the demand curve to measure consumer surplus.Figure 1 “This represents the demand curve for the time machine. Consumer surplus is the difference between what consumers are willing to pay and the amount they actually have to pay. The market price will deter mine who uses the time machine and how much surplus they keep.”“If the price of a time machine ride was $500, three rides would be sold—one to Scott, one to Carol, and one to Steve. Jeanne is not willing to pay $500, so she wouldn’t time travel.”“We c an calculate the consumer surplus of three time trips. Scott would pay $3,000 but only pays $500, leaving $2,500 of net benefits.” (Put these numbers on the board.) “Carol has net benefits of $2,000. Steve has $300 in net benefits. Adding up these net savings gives $4,800 in consumer surplus.”Points for DiscussionThe consumer surplus depends on a good’s selling price and the number of consumers who are willing to purchase the good at that price. The lower the price, the greater the consumer surplus.3. Consumer surplus can be measured as the area below the demand curve and above the price. C. How a Lower Price Raises Consumer Surplus1. As price falls, consumer surplus increases for two reasons.a. Those already buying the product will receive additional consumer surplus because theyare paying less for the product than before (area A on the graph).b. Because the price is now lower, some new buyers will enter the market and receiveconsumer surplus on these additional units of output purchased (area B on the graph).D. What Does Consumer Surplus Measure?1. Remember that consumer surplus is the difference between the amount that buyers arewilling to pay for a good and the price that they actually pay.2. Thus, it measures the benefit that consumers receive from the good as the buyersthemselves perceive it.Figure 2Figure 3It is important to stress that consumer surplus is measured in monetary terms. Consumer surplus gives us a way to place a monetary cost on inefficient market outcomes (due to government involvement or market failure).III. Producer SurplusA. Cost and the Willingness to Sell1. Definition of cost: the value of everything a seller must give up to produce a good .2. Example: You want to hire someone to paint your house. You accept bids for the work fromfour sellers. Each painter is willing to work if the price you will pay exceeds her opportunity cost. (Note that this opportunity cost thus represents willingness to sell.) The costs are:3. Bidding will stop when the price gets to be slightly below $600. All sellers will drop out exceptfor Grandma. Because Grandma receives more than she would require to paint the house, she derives some benefit from producing in the market.4. Definition of producer surplus: the amount a seller is paid for a good minus theseller’s cost of providing it.5. Note that if you had more than one house to paint, the price in the auction would end upbeing higher (a little under $800 in the case of two houses) and both Grandma and Georgia would gain producer surplus.ALTERNATIVE CLASSROOM EXAMPLE:Review the material on price ceilings from Chapter 6. Redraw the market for two-bedroom apartments in your town. Draw in a price ceiling below the equilibrium price.Then go through:▪ consumer surplus before the price ceiling is put into place. ▪ consumer surplus after the price ceiling is put into place.B. Using the Supply Curve to Measure Producer Surplus1. We can use the information on cost (willingness to sell) to derive a supply curve for housepainting services.Price Sellers Quantity Supplied$900 or more Mary, Frida, Georgia, Grandma 4$800 to $900 Frida, Georgia, Grandma 3$600 to $800 Georgia, Grandma 2$500 to $600 Grandma 1less than $500 None 02. At any given quantity, the price given by the supply curve represents the cost of the marginalseller. Because the supply curve shows the sellers’ cost (willingness to sell), we can use the supply curve to measure producer surplus.3. Producer surplus can be measured as the area above the supply curve and below the price. Figure 4Figure 5C. How a Higher Price Raises Producer Surplus1. As price rises, producer surplus increases for two reasons.a. Those already selling the product will receive additional producer surplus because theyare receiving more for the product than before (area C on the graph).b. Because the price is now higher, some new sellers will enter the market and receiveproducer surplus on these additional units of output sold (area D on the graph).D. Producer surplus is used to measure the economic well-being of producers, much like consumersurplus is used to measure the economic well-being of consumers.Figure 6ALTERNATIVE CLASSROOM EXAMPLE:Review the material on price floors from Chapter 6. Redraw the market for an agriculturalproduct such as corn. Draw in a price support above the equilibrium price.Then go through:▪ producer surplus before the price support is put in place.▪ producer surplus after the price support is put in place.Make sure that you discuss the cost of the price support to taxpayers.Pretty Woman, Chapter 6. Vivien (Julia Roberts) and Edward (Richard Gere)negotiate a price. Afterward, Vivien reveals she would have accepted a lower price,while Edward admits he would have paid more. If you have done a good job ofintroducing consumer and producer surplus, you will see the light bulbs go off aboveyour students’ heads as they watch this clip.IV. Market EfficiencyA. The Benevolent Social Planner1. The economic well-being of everyone in society can be measured by total surplus, which isthe sum of consumer surplus and producer surplus:Total Surplus = Consumer Surplus + Producer SurplusTotal Surplus = (Value to Buyers – Amount Paid by Buyers) + (Amount Received by Sellers – Cost to Sellers)Because the Amount Paid by Buyers = Amount Received by Sellers:2. Definition ofefficiency: the property of a resource allocation of maximizing thetotal surplus received by all members of society .3. Definition of equality: the property of distributing economic prosperity uniformlythe members of society .B. Evaluating the Market EquilibriumTotal Surplus = Value to Buyers Cost to Sellers Figure 7Now might be a good time to point out that many government policies involve atrade-off between efficiency and equity. When you evaluate government policies, like price ceilings or floors, you can explain them in terms of equity and efficiency.1. At the market equilibrium price:a. Buyers who value the product more than the equilibrium price will purchase the product;those who do not, will not purchase the product. In other words, the free marketallocates the supply of a good to the buyers who value it most highly, as measured bytheir willingness to pay.b. Sellers whose costs are lower than the equilibrium price will produce the product; thosewhose costs are higher, will not produce the product. In other words, the free marketallocates the demand for goods to the sellers who can produce it at the lowest cost.2. Total surplus is maximized at the market equilibrium.Figure 8a. At any quantity of output smaller than the equilibrium quantity, the value of the productto the marginal buyer is greater than the cost to the marginal seller so total surpluswould rise if output increases.b. At any quantity of output greater than the equilibrium quantity, the value of the productto the marginal buyer is less than the cost to the marginal seller so total surplus wouldrise if output decreases.3. Note that this is one of the reasons that economists believe Principle #6: Markets are usuallya good way to organize economic activity.It would be a good idea to remind students that there are circumstances when themarket process does not lead to the most efficient outcome. Examples includesituations such as when a firm (or buyer) has market power over price or when thereare externalities present. These situations will be discussed in later chapters.C. In the News: Ticket Scalping1. Ticket scalping is an example of how markets work to achieve an efficient outcome.2. This article from The Boston Globe descri bes economist Chip Case’s experience with ticketscalping.D. Case Study: Should There Be a Market in Organs?1. As a matter of public policy, people are not allowed to sell their organs.a. In essence, this means that there is a price ceiling on organs of $0.b. This has led to a shortage of organs.2. The creation of a market for organs would lead to a more efficient allocation of resources,but critics worry about the equity of a market system for organs.V. Market Efficiency and Market FailureA. To conclude that markets are efficient, we made several assumptions about how markets worked.1. Perfectly competitive markets.2. No externalities.B. When these assumptions do not hold, the market equilibrium may not be efficient.C. When markets fail, public policy can potentially remedy the situation.SOLUTIONS TO TEXT PROBLEMS:Quick Quizzes1. Figure 1 shows the demand curve for turkey. The price of turkey is P1 and the consumersurplus that results from that price is denoted CS. Consumer surplus is the amount a buyer iswilling to pay for a good minus the amount the buyer actually pays for it. It measures thebenefit to buyers of participating in a market.Figure 1 Figure 22. Figure 2 shows the supply curve for turkey. The price of turkey is P1 and the producersurplus that results from that price is denoted PS. Producer surplus is the amount sellers arepaid for a good minus the sellers’ cost of providing it (measured by the supply curve). Itmeasures the benefit to sellers of participating in a market.Figure 33. Figure 3 shows the supply and demand for turkey. The price of turkey is P1, consumersurplus is CS, and producer surplus is PS. Producing more turkeys than the equilibriumquantity would lower total surplus because the value to the marginal buyer would be lowerthan the cost to the marginal seller on those additional units.Questions for Review1. The price a buyer is willing to pay, consumer surplus, and the demand curve are all closelyrelated. The height of the demand curve represents the willingness to pay of the buyers.Consumer surplus is the area below the demand curve and above the price, which equals theprice that each buyer is willing to pay minus the price actually paid.2. Sellers' costs, producer surplus, and the supply curve are all closely related. The height of thesupply curve represents the costs of the sellers. Producer surplus is the area below the priceand above the supply curve, which equals the price received minus each seller's costs ofproducing the good.Figure 43. Figure 4 shows producer and consumer surplus in a supply-and-demand diagram.4. An allocation of resources is efficient if it maximizes total surplus, the sum of consumersurplus and producer surplus. But efficiency may not be the only goal of economicpolicymakers; they may also be concerned about equity the fairness of the distribution ofwell-being.5. The invisible hand of the marketplace guides the self-interest of buyers and sellers intopromoting general economic well-being. Despite decentralized decision making and self-interested decision makers, free markets often lead to an efficient outcome.6. Two types of market failure are market power and externalities. Market power may causemarket outcomes to be inefficient because firms may cause price and quantity to differ fromthe levels they would be under perfect competition, which keeps total surplus from beingmaximized. Externalities are side effects that are not taken into account by buyers and sellers.As a result, the free market does not maximize total surplus.Problems and Applications1. a. Consumer surplus is equal to willingness to pay minus the price paid. Therefore,Melissa’s willingness to pay must be $200 ($120 + $80).b. Her consumer surplus at a price of $90 would be $200 − $90 = $110.c. If the price of an iPod was $250, Melissa would not have purchased one because theprice is greater than her willingness to pay. Therefore, she would receive no consumersurplus.2. If an early freeze in California sours the lemon crop, the supply curve for lemons shifts to theleft, as shown in Figure 5. The result is a rise in the price of lemons and a decline inconsumer surplus from A + B + C to just A. So consumer surplus declines by the amount B +C.Figure 5 Figure 6In the market for lemonade, the higher cost of lemons reduces the supply of lemonade, asshown in Figure 6. The result is a rise in the price of lemonade and a decline in consumersurplus from D + E + F to just D, a loss of E + F. Note that an event that affects consumersurplus in one market often has effects on consumer surplus in other markets.3. A rise in the demand for French bread leads to an increase in producer surplus in the marketfor French bread, as shown in Figure 7. The shift of the demand curve leads to an increased price, which increases producer surplus from area A to area A + B + C.Figure 7The increased quantity of French bread being sold increases the demand for flour, as shown in Figure 8. As a result, the price of flour rises, increasing producer surplus from area D to D + E + F. Note that an event that affects producer surplus in one market leads to effects on producer surplus in related markets.Figure 84. a. Bert’s demand schedule is:Price Quantity DemandedMore than $7 0$5 to $7 1$3 to $5 2$1 to $3 3$1 or less 4Bert’s demand curve is shown in Figure 9.Figure 9b. When the price of a bottle of water is $4, Bert buys two bottles of water. His consumersurplus is shown as area A in the figure. He values his first bottle of water at $7, butpays only $4 for it, so has consumer surplus of $3. He values his second bottle of water at $5, but pays only $4 for it, so has consumer surplus of $1. Thus Bert’s total consumer surplus is $3 + $1 = $4, which is the area of A in the figure.c. When the price of a bottle of water falls from $4 to $2, Bert buys three bottles of water,an increase of one. His consumer surplus consists of both areas A and B in the figure, an increase in the amount of area B. He gets consumer surplus of $5 from the first bottle($7 value minus $2 price), $3 from the second bottle ($5 value minus $2 price), and $1 from the third bottle ($3 value minus $2 price), for a total consumer surplus of $9. Thus consumer surplus rises by $5 (which is the size of area B) when the price of a bottle ofwater falls from $4 to $2.5. a. Ernie’s supply schedule for water is:Price Quantity SuppliedMore than $7 4$5 to $7 3$3 to $5 2$1 to $3 1Less than $1 0Ernie’s supply curve is shown in Figure 10.Figure 10b. When the price of a bottle of water is $4, Ernie sells two bottles of water. His producersurplus is shown as area A in the figure. He receives $4 for his first bottle of water, but itcosts only $1 to produce, so Ernie has producer surplus of $3. He also receives $4 for his second bottle of water, which costs $3 to produce, so he has producer surplus of $1.Thus Ernie’s total producer surplus is $3 + $1 = $4, which is the area of A in the figure.c. When the price of a bottle of water rises from $4 to $6, Ernie sells three bottles of water,an increase of one. His producer surplus consists of both areas A and B in the figure, anincrease by the amount of area B. He gets producer surplus of $5 from the first bottle($6 price minus $1 cost), $3 from the second bottle ($6 price minus $3 cost), and $1from the third bottle ($6 price minus $5 price), for a total producer surplus of $9. Thusproducer surplus rises by $5 (which is the size of area B) when the price of a bottle ofwater rises from $4 to $6.6. a. From Ernie’s supply schedule and Bert’s demand schedule, the quantity demanded andsupplied are:Price Quantity Supplied Quantity Demanded$2 1 3$4 2 2$6 3 1Only a price of $4 brings supply and demand into equilibrium, with an equilibriumquantity of two.b. At a price of $4, consumer surplus is $4 and producer surplus is $4, as shown inProblems 3 and 4 above. Total surplus is $4 + $4 = $8.c. If Ernie produced one less bottle, his producer surplus would decline to $3, as shown inProblem 4 above. If Bert consumed one less bottle, his consumer surplus would declineto $3, as shown in Problem 3 above. So total surplus would decline to $3 + $3 = $6.d. If Ernie produced one additional bottle of water, his cost would be $5, but the price isonly $4, so his producer surplus would decline by $1. If Bert consumed one additionalbottle of water, his value would be $3, but the price is $4, so his consumer surplus would decline by $1. So total surplus declines by $1 + $1 = $2.7. a. The effect of falling production costs in the market for stereos results in a shift to theright in the supply curve, as shown in Figure 11. As a result, the equilibrium price ofstereos declines and the equilibrium quantity increases.Figure 11b. The decline in the price of stereos increases consumer surplus from area A to A + B + C+ D, an increase in the amount B + C + D. Prior to the shift in supply, producer surpluswas areas B + E (the area above the supply curve and below the price). After the shift in supply, producer surplus is areas E + F + G. So producer surplus changes by the amountF +G – B, which may be positive or negative. The increase in quantity increasesproducer surplus, while the decline in the price reduces producer surplus. Becauseconsumer surplus rises by B + C + D and producer surplus rises by F + G – B, totalsurplus rises by C + D + F + G.c. If the supply of stereos is very elastic, then the shift of the supply curve benefitsconsumers most. To take the most dramatic case, suppose the supply curve werehorizontal, as shown in Figure 12. Then there is no producer surplus at all. Consumerscapture all the benefits of falling production costs, with consumer surplus rising fromarea A to area A + B.Figure 128. Figure 13 shows supply and demand curves for haircuts. Supply equals demand at a quantityof three haircuts and a price between $4 and $5. Firms A, C, and D should cut the hair of Ellen, Jerry, and Phil. Oprah’s willingness to pay is too low and firm B’s costs are too high, so they do not participate. The maximum total surplus is the area between the demand and supply curves, which totals $11 ($8 value minus $2 cost for the first haircut, plus $7 value minus $3 cost for the second, plus $5 value minus $4 cost for the third).Figure 139. a. The effect of falling production costs in the market for computers results in a shift to theright in the supply curve, as shown in Figure 14. As a result, the equilibrium price ofcomputers declines and the equilibrium quantity increases. The decline in the price ofcomputers increases consumer surplus from area A to A + B + C + D, an increase in the amount B + C + D.Figure 14 Figure 15Prior to the shift in supply, producer surplus was areas B + E (the area above the supply curve and below the price). After the shift in supply, producer surplus is areas E + F + G.So producer surplus changes by the amount F + G – B, which may be positive ornegative. The increase in quantity increases producer surplus, while the decline in theprice reduces producer surplus. Because consumer surplus rises by B + C + D andproducer surplus rises by F + G – B, total surplus rises by C + D + F + G.b. Because typewriters are substitutes for computers, the decline in the price of computersmeans that people substitute computers for typewriters, shifting the demand fortypewriters to the left, as shown in Figure 15. The result is a decline in both theequilibrium price and equilibrium quantity of typewriters. Consumer surplus in thetypewriter market changes from area A + B to A + C, a net change of C – B. Producersurplus changes from area C + D + E to area E, a net loss of C + D. Typewriterproducers are sad about technological advances in computers because their producersurplus declines.c. Because software and computers are complements, the decline in the price and increasein the quantity of computers means that the demand for software increases, shifting the demand for software to the right, as shown in Figure 16. The result is an increase in both the price and quantity of software. Consumer surplus in the software market changesfrom B + C to A + B, a net change of A – C. Producer surplus changes from E to C + D + E, an increase of C + D, so software producers should be happy about the technological progress in computers.Figure 16d. Yes, this analysis helps explain why Bill Gates is one the world’s richest people, becausehis company produces a lot of software that is a complement with computers and therehas been tremendous technological advance in computers.10. a. With Provider A, the cost of an extra minute is $0. With Provider B, the cost of an extraminute is $1.b. With Provider A, my friend will purchase 150 minutes [= 150 – (50)(0)]. With Provider B,my friend would purchase 100 minutes [= 150 – (50)(1)].c. With Provider A, he would pay $120. The cost would be $100 with Provider B.Figure 17d. Figure 17 shows the friend’s demand. With Provider A, he buys 150 minu tes and hisconsumer surplus is equal to (1/2)(3)(150) – 120 = 105. With Provider B, his consumersurplus is equal to (1/2)(2)(100) = 100.e. I would recommend Provider A because he receives greater consumer surplus.11. a. Figure 18 illustrates the demand for medical care. If each procedure has a price of $100,quantity demanded will be Q1 procedures.Figure 18b. If consumers pay only $20 per procedure, the quantity demanded will be Q2 procedures.Because the cost to society is $100, the number of procedures performed is too large to maximize total surplus. The quantity that maximizes total surplus is Q1 procedures, which is less than Q2.c. The use of medical care is excessive in the sense that consumers get procedures whosevalue is less than t he cost of producing them. As a result, the economy’s total surplus is reduced.d. To prevent this excessive use, the consumer must bear the marginal cost of theprocedure. But this would require eliminating insurance. Another possibility would be that the insurance company, which pays most of the marginal cost of the procedure ($80, in this case) could decide whether the procedure should be performed. But the insurance company does not get the benefits of the procedure, so its decisions may not reflect the value to the consumer.。

第三篇市场和福利第七章消费者、生产者与市场效率问题与应用1．Melissa用120美元购买了一个iPod，并得到了80美元的消费者剩余。

A．她的支付意愿是多少？答：消费者剩余等于支付意愿减去付出的价格。

因此，梅莉莎须支付200 美元($120 + $80)。

B．如果她在降价销售时买了售价为90美元的iPod，她的消费者剩余会是多少？答：此时，她的消费者剩余为：200-90 =110 美元。

C．如果iPod的价格是250美元，她的消费者剩余会是多少？答：如果iPod 的价格是250 美元，其价格大于梅莉莎的支付愿意，因此她不会再买，这时的消费者剩余就为零。

2．加利福尼亚早来的寒流使柠檬变酸。

柠檬市场上消费者剩余会有什么变动？柠檬水市场上消费者剩余会有什么变动？用图形说明你的答案。

答：柠檬变酸，消费者对柠檬的评价下降，需求曲线向左下方移动。

在其他条件不变的情况下，消费者剩余减少。

如图7－2(a)所示，柠檬质量下降，使需求曲线从D1下降到D 2，△APE是原先的消费者剩余，△A′P′E′是变动后的消费者剩余，△APE>△A′P′E′。

由于柠檬价格的下降，柠檬水的投入成本减少，柠檬水的价格也下降。

在其他条件不变的情况下，柠檬水市场上消费者剩余增加，如图7－2(b)所示。

图7－2 寒流的影响3．假设对法国面包的需求增加。

在法国面包市场上，生产者剩余会发生什么变动？在面粉市场上，生产者剩余会发生什么变动？用图形说明你的答案。

答：由于需求增加，在其他条件不变的情况下，法国面包的价格会上升，市场上的生产者剩余增加。

如图7 －3(a)，价格从P1 上升到P2 ，销量从Q 1上升到Q 2，生产者剩余从面积P1BE1增加到面积P2BE2 。

由于面包产量上升，它的生产要素面粉的需求量也会上升。

在其他条件不变的情况下，面粉价格上升，市场上的生产者剩余增加。

如图7－3(b)所示，生产者剩余从面积P1BE1增加到面积P2BE2 。