下载文档原格式
曼昆《经济学原理（微观经济学分册）》（第6版）第11章公共物品和公共资源课后习题详解跨考网独家整理最全经济学考研真题，经济学考研课后习题解析资料库，您可以在这里查阅历年经济学考研真题，经济学考研课后习题，经济学考研参考书等内容，更有跨考考研历年辅导的经济学学哥学姐的经济学考研经验，从前辈中获得的经验对初学者来说是宝贵的财富，这或许能帮你少走弯路，躲开一些陷阱。
以下内容为跨考网独家整理，如您还需更多考研资料，可选择经济学一对一在线咨询进行咨询。
一、概念题1．排他性（excludability）答：排他性指一个人使用或消费一种产品或服务时可以阻止其他人使用或消费该种产品和服务的特性。
一种产品或服务具有排他性时，一个人使用或消费该产品或服务时可以阻止其他人使用或消费该种产品和服务。
排他性是区分公共物品和私人物品的标准之一。
生产者的排他原则有效时，生产者能够限制那些不为这种物品支付的消费者使用这种商品，消费者的排他性有效时，消费者在消费一种物品时，其他人能够被排除在外。
在排他性原则失效的地方，就会出现没有付出代价，却可以享受物品效用的“免费搭便车”现象。
2．消费中的竞争性（rivalry in consumption）答：消费中的竞争性指一种产品或服务被一个人消费从而减少了其他人消费的特性。
如果某人已经使用了某个商品（如某一火车座位），其他人就不能再同时使用该商品，则这种商品就具有消费中的竞争性。
市场机制只有在具备排他性和竞争性两个特点的私人物品的场合才真正起作用，才有效率。
3．私人物品（private goods）答：私人物品指既有排他性又有竞争性的物品，是供个人单独消费的物品。
私人物品是那种可得数量将随任何人对它的消费或使用的增加而减少的物品，它具有两个特征：第一是竞争性，如果某人已消费了某种商品，则其他人就不能再消费该商品；第二是排他性，对商品支付价格的人才能消费商品，其他人则不能。
4．公共物品（public goods）（西北大学2003研；北京师范大学2007研；华南理工大学2010研）答：公共物品与私人物品相对应，指既无排他性又无竞争性的物品。
经济学基础学习知识（曼昆）课后习题集规范标准答案第一章经济学十大原理一、为每个关键术语选择一个定义关键术语定义--------------稀缺性1、在社会成员中平等地分配利益的特征--------------经济学2、市场不能有效的配置资源的状况--------------效率3、有限的资源和无限的欲望--------------平等4、一个工人一小时所生产的物品与劳务量--------------理性5、市场上只有一个买者的情况--------------机会成本6、利己的市场参与者可以不知不觉的使整体社会福利最大化的原理--------------边际变动7、社会从其稀缺资源中得到最多东西的特性--------------激励8、社会和企业在市场上的相互交易决定资源配置的经济--------------市场经济9、经济活动的波动--------------产权10、当一个人的行为对旁观者有影响时的情况--------------“看不见的手”11、物价总水平的上升--------------市场失灵12、对现行计划的增量调整--------------外部性13、研究社会如何管理其稀缺资源--------------市场势力14、得到某种东西所放弃的东西--------------垄断15、一个人或一群人不适当的影响市场价格的能力--------------生产率16、某种引起人行动的东西--------------通货膨胀17、一个人拥有并使用稀缺资源的能力--------------经济周期18、为了达到目标而尽可能系统性的做到最好二、判断正误--------------1、当政府用税收和福利再分配收入时，经济变得更有效率。
-------------2、当经济学家说“天下没有免费的午餐”时，他们是指所有经济决策都涉及权衡取舍。
-------------3、亚当斯密的“看不见的手”的概念描述了公司经营如何像一只“看不见的手”伸到消费者的钱包中。
曼昆《经济学原理（微观经济学分册）》（第6版）第15章垄断课后习题详解跨考网独家整理最全经济学考研真题，经济学考研课后习题解析资料库，您可以在这里查阅历年经济学考研真题，经济学考研课后习题，经济学考研参考书等内容，更有跨考考研历年辅导的经济学学哥学姐的经济学考研经验，从前辈中获得的经验对初学者来说是宝贵的财富，这或许能帮你少走弯路，躲开一些陷阱。
以下内容为跨考网独家整理，如您还需更多考研资料，可选择经济学一对一在线咨询进行咨询。
一、概念题1．垄断企业（monopoly firms）（西北大学2006研）答：垄断企业指一种没有相近替代品的产品的唯一卖者的企业。
垄断是这样一种状态：在某一市场上只存在一个厂商，这一厂商在这个市场上拥有绝对的权力，它控制该市场的全部供给，从而能决定价格和销售数量。
此外，该厂商还控制着所有有关市场与价格的信息。
垄断从分配的角度来看是垄断者得到了全部利益而消费者一无所获。
在各种类型的市场中，垄断市场一般被认为是效率最低的市场，而且阻碍了技术进步。
但是，有的西方学者认为，垄断厂商资金雄厚，可以从事革新生产技术的长期研究。
2．自然垄断（natural monopoly）（西北大学2003、2005研；深圳大学2012研）答：自然垄断指某些行业或部门为了有效生产而只需要一个生产者或厂商的市场状况。
这种行业可能始终呈现规模经济的特征，若由两家或两家以上的厂商生产将产生较高的平均成本、造成社会资源的浪费。
自然垄断部门一般有电力、石油、天然气、自来水和电信等行业。
自然垄断的形成，使得一个大规模厂商能够依靠自己的规模经济来降低生产成本，使得规模经济的益处由该厂商充分加以利用。
自然垄断有时来源于某些地理条件。
在自然垄断的部门中，政府通常对厂商加以认可，以批准该厂商进入该行业经营，或者在不利后果发生之前进行制止，以免损害公共利益。
政府管制自然垄断部门的原因在于：①如果自然垄断行业内竞争性厂商过多，会造成经济资源的巨大浪费。
目 录第1篇 导 言第1章 经济学十大原理第2章 像经济学家一样思考第3章 相互依存性与贸易的好处第2篇 市场如何运行第4章 供给与需求的市场力量第5章 弹性及其应用第6章 供给、需求与政府政策第3篇 市场和福利第7章 消费者、生产者与市场效率第8章 应用：赋税的代价第9章 应用：国际贸易第4篇 公共部门经济学第10章 外部性第11章 公共物品和公共资源第12章 税制的设计第5篇 企业行为与产业组织第13章 生产成本第14章 竞争市场上的企业第15章 垄 断第16章 垄断竞争第17章 寡 头第6篇 劳动市场经济学第18章 生产要素市场第19章 收入与歧视第20章 收入不平等与贫困第7篇 深入研究的论题第21章 消费者选择理论第22章 微观经济学前沿第1篇 导 言第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。
曼昆《经济学原理（微观经济学分册）》（第6版）第11章公共物品和公共资源复习笔记跨考网独家整理最全经济学考研真题，经济学考研课后习题解析资料库，您可以在这里查阅历年经济学考研真题，经济学考研课后习题，经济学考研参考书等内容，更有跨考考研历年辅导的经济学学哥学姐的经济学考研经验，从前辈中获得的经验对初学者来说是宝贵的财富，这或许能帮你少走弯路，躲开一些陷阱。
以下内容为跨考网独家整理，如您还需更多考研资料，可选择经济学一对一在线咨询进行咨询。
一、不同类型的物品1．相关概念：（1）排他性：一种物品具有的可以阻止一个人使用该物品的特性。
（2）消费者的竞争性：一个人使用一种物品将减少其他人对该物品的使用的特性。
（3）私人物品（private goods）：消费中既有排他性又有竞争性的物品。
（4）公共资源：有竞争性但无排他性的物品。
（5）公共物品：既无排他性又无竞争性的物品。
（6）自然垄断：当一种物品在消费中有排他性但没有竞争性时，就是自然垄断的物品。
2．四种类型的物品根据物品的排他性和消费竞争性可以将物品分为四种类型，如图11-1所示。
物品在消费中有没有排他性或竞争性往往是一个程度问题，有时候界限模糊，难以区分。
图11-1 四种类型的物品二、公共物品1．搭便车者问题搭便车者：得到一种物品的利益但避开为此付费的人。
由于公共物品没有排他性，搭便车者问题的存在就使私人市场无法提供公共物品。
但是，政府可以潜在地解决这个问题。
如果政府确信一种公共物品的总利益大于成本，它就可以提供该公共物品，并用税收收入对其进行支付，从而可以使每个人的状况变好。
2．一些重要的公共物品考虑三种重要的公共物品：国防、基础研究、反贫困。
（1）国防国防既无排他性，也无竞争性。
国防是政府应该提供的公共物品。
（2）基础研究基础研究可以通过研究创造出知识。
知识可区分为一般性知识与特定知识：①特定技术知识可以申请专利，专利使发明者创造的知识具有了排他性，这将激励企业拿出资金用于新产品开发的研究中，以便获得专利并出售；②一般性知识是公共物品，既无排他性，也无竞争性，企业往往搭一般知识的便车，很少在上面投资。
MONOPOLISTIC COMPETITIONWHAT’S NEW IN THE S EVENTH EDITION:There are no major changes to this chapter.LEARNING OBJECTIVES:By the end of this chapter, students should understand:what market structures lie between monopoly and competition.competition among firms that sell differentiated products.how the outcomes under monopolistic competition and under perfect competition compare.the desirability of outcomes in monopolistically competitive markets.the debate over the effects of advertising.the debate over the role of brand names.CONTEXT AND PURPOSE:Chapter 16 is the fourth chapter in a five-chapter sequence dealing with firm behavior and the organization of industry. The previous two chapters developed the two extreme forms of market structure—competition and monopoly. The market structure that lies between competition and monopoly is known as imperfect competition. There are two types of imperfect competition—monopolistic competition and oligopoly. This chapter addresses monopolistic competition while the final chapter in the sequence addresses oligopoly. The analysis in this chapter is again based on the cost curves developed in Chapter 13.The purpose of Chapter 16 is to address monopolistic competition—a market structure in which many firms sell products that are similar but not identical. Monopolistic competition differs from perfect competition because each of the many sellers offers a somewhat different product. As a result, monopolistically competitive firms face a downward-sloping demand curve while competitive firms face a horizontal demand curve at the market price. Monopolistic competition is extremely common.KEY POINTS:A monopolistically competitive market is characterized by three attributes: many firms, differentiatedproducts, and free entry.The long-run equilibrium in a monopolistically competitive market differs from that in a perfectly competitive market in two related ways. First, each firm in a monopolistically competitive market has excess capacity. That is, it chooses a quantity that puts it on the downward-sloping portion of the average-total-cost curve. Second, each firm charges a price above marginal cost.Monopolistic competition does not have all of the desirable properties of perfect competition. There is the standard deadweight loss of monopoly caused by the markup of price over marginal cost. In addition, the number of firms (and thus the variety of products) can be too large or too small. In practice, the ability of policymakers to correct these inefficiencies is limited.The product differentiation inherent in monopolistic competition leads to the use of advertising and brand names. Critics of advertising and brand names argue that firms use them to manipulate consumers’ tastes and to reduce competition. Defenders of advertising and brand names argue that firms use them to informconsumers and to compete more vigorously on price and product quality.CHAPTER OUTLINE:I. Between Monopoly and Perfect CompetitionA. The typical firm has some market power, but its market power is not as great as that described bymonopoly.B. Firms in imperfect competition lie somewhere between the competitive model and the monopoly model.C. Definition of oligopoly: a market structure in which only a few sellers offer similar or identical products.1. Economists measure a market’s domination by a small number of firms with a statistic called aconcentration ratio.2. The concentration ratio is the percentage of total output in the market supplied by the four largestfirms.3. In the . economy, most industries have a four-firm concentration ratio under 50%.D. Definition of monopolistic competition: a market structure in which many firms sell products that aresimilar but not identical.1. Characteristics of Monopolistic Competitiona. Many Sellersb. Product Differentiationc. Free EntryE. Figure 1 summarizes the four types of market structure. Note that it is the number of firms and the typeof product sold that distinguishes one market structure from another.II. Competition with Differentiated ProductsA. The Monopolistically Competitive Firm in the Short Run1. Each firm in monopolistic competition faces a downward-sloping demand curve because its product isdifferent from those offered by other firms.2. The monopolistically competitive firm follows a monopolist's rule for maximizing profit.a. It chooses the output level where marginal revenue is equal to marginal cost.b. It sets the price using the demand curve to ensure that consumers will demand exactly theamount produced.Figure 23. We can determine whether or not the monopolistically competitive firm is earning a profit or loss bycomparing price and average total cost.a. If P > ATC, the firm is earning a profit.b. If P < ATC, the firm is earning a loss.c. If P = ATC, the firm is earning zero economic profit.B. The Long-Run Equilibrium1. When firms in monopolistic competition are making profit, new firms have an incentive to enter themarket.a. This increases the number of products from which consumers can choose.b. Thus, the demand curve faced by each firm shifts to the left.c. As the demand falls, these firms experience declining profit.2. When firms in monopolistic competition are incurring losses, firms in the market will have anincentive to exit.a. Consumers will have fewer products from which to choose.b. Thus, the demand curve for each firm shifts to the right.c. The losses of the remaining firms will fall.3. The process of exit and entry continues until the firms in the market are earning zero profit.a. This means that the demand curve and the average-total-cost curve are tangent to each other.b. At this point, price is equal to average total cost and the firm is earning zero economic profit. Figure 3Remember that students have a hard time understanding why a firm will continue tooperate if it is earning “only” zero economic profit. Remind them that zero economic profitmeans that firms are earning an accounting profit equal to their implicit costs.Point out to students that, just like firms in perfect competition, firms in monopolisticcompetition also earn zero economic profit in the long run. Show them that this result occursbecause firms can freely enter the market when profits occur, driving the level of profits tozero. Any market with no barriers to entry will see zero economic profit in the long run.4. There are two characteristics that describe the long-run equilibrium in a monopolistically competitivemarket.a. Price exceeds marginal cost (due to the fact that each firm faces a downward-sloping demandcurve).b. Price equals average total cost (due to the freedom of entry and exit).C. Monopolistic versus Perfect CompetitionFigure 41. Excess Capacitya. The quantity of output produced by a monopolistically competitive firm is smaller than thequantity that minimizes average total cost (the efficient scale).b. This implies that firms in monopolistic competition have excess capacity, because the firm couldincrease its output and lower its average total cost of production.c. Because firms in perfect competition produce where price is equal to the minimum average totalcost, firms in perfect competition produce at their efficient scale.2. Markup over Marginal Costa. In monopolistic competition, price is greater than marginal cost because the firm has somemarket power.b. In perfect competition, price is equal to marginal cost.D. Monopolistic Competition and the Welfare of Society1. One source of inefficiency is the markup over marginal cost. This implies a deadweight loss (similar tothat caused by monopolies).2. Because there are so many firms in this type of market structure, regulating these firms would bedifficult.3. Also, forcing these firms to set price equal to marginal cost would force them out of business(because they are already earning zero economic profit).4. There are also externalities associated with entry.a. The product-variety externality occurs because as new firms enter, consumers get someconsumer surplus from the introduction of a new product. Note that this is a positive externality.b. The business-stealing externality occurs because as new firms enter, other firms lose customersand profit. Note that this is a negative externality.c. Depending on which externality is larger, a monopolistically competitive market could have toofew or too many products.5. In the News: Insufficient Variety as a Market Failurea. Firms may insufficiently service consumers with unusual preferences in markets with large fixedcostsb. This article from Slate describes how some consumers get left out of the market because of thehigh fixed costs associated with creating additional varieties of a product.III. AdvertisingA. The Debate over Advertising1. The Critique of Advertisinga. Firms advertise to manipulate people's tastes.b. Advertising impedes competition because it increases the perception of product differentiationand fosters brand loyalty. This means that consumers will be less concerned with pricedifferences among similar goods.2. The Defense of Advertisinga. Firms use advertising to provide information to consumers.b. Advertising fosters competition because it allows consumers to be better informed about all ofthe firms in the market.3. Case Study: Advertising and the Price of Eyeglassesa. In the United States during the 1960s, states differed on whether or not they allowed advertisingfor optometrists.b. In the states that prohibited advertising, the average price paid for a pair of eyeglasses in 1963was $33; in states that allowed advertising, the average price was $26 (a difference of more than20%).B. Advertising as a Signal of Quality1. The willingness of a firm to spend a large amount of money on advertising may be a signal toconsumers about the quality of the product being offered.2. Example: Kellogg and Post have each developed a new cereal that would sell for $3 per box. (Assumethat the marginal cost of producing the cereal is zero.) Each company knows that if it spends $10million on advertising, it will get one million new consumers to try the product. If consumers like the product, they will buy it again.a. Post has discovered through market research that its new cereal is not very good. After buying itonce, consumers would not likely buy it again. Thus, it will only earn $3 million in revenue, whichwould not be enough to pay for the advertising. Therefore, it does not advertise.b. Kellogg knows that its cereal is great. Each person that buys it will likely buy one box per monthfor the next year. Therefore, its sales would be $36 million, which is more than enough to justifythe advertisement.c. By its willingness to spend money on advertising, Kellogg signals to consumers the quality of itscereal.3. Note that the content of the advertisement is unimportant; what is important is that consumersknow that the advertisements are expensive.C. Brand Names1. In many markets there are two types of firms; some firms sell products with widely recognized brandnames while others sell generic substitutes.2. Critics of brand names argue that they cause consumers to perceive differences that do not reallyexist.3. Economists have defended brand names as a useful way to ensure that goods are of high quality.a. Brand names provide consumers with information about quality when quality cannot be judgedeasily in advance of purchase.b. Brand names give firms an incentive to maintain high quality, because firms have a financialstake in maintaining the reputation of their brand names.SOLUTIONS TO TEXT PROBLEMS:Quick Quizzes1. Oligopoly is a market structure in which only a few sellers offer similar or identical products.Examples include the market for breakfast cereals and the world market for crude oil. Monopolisticcompetition is a market structure in which many firms sell products that are similar but not identical.Examples include the markets for novels, movies, restaurant meals, and computer games.2. The three key attributes of monopolistic competition are: (1) there are many sellers; (2) each firmproduces a slightly different product; and (3) firms can enter or exit the market freely.Figure 1 shows the long-run equilibrium in a monopolistically competitive market. This equilibriumdiffers from that in a perfectly competitive market because price exceeds marginal cost and the firmdoes not produce at the minimum point of average total cost but instead produces at less than theefficient scale.Figure 13. Advertising may make markets les s competitive if it manipulates people’s tastes rather than beinginformative. Advertising may give consumers the perception that there is a greater differencebetween two products than really exists. That makes the demand curve for a product more inelastic,so the firms can then charge greater markups over marginal cost. However, some advertising couldmake markets more competitive because it sometimes provides useful information to consumers,allowing them to take advantage of price differences more easily. Advertising also facilitates entrybecause it can be used to inform consumers about a new product. In addition, expensive advertisingcan be a signal of quality.Brand names may be beneficial because they provide information to consumers about the quality ofgoods. They also give firms an incentive to maintain high quality, since their reputations areimportant. But brand names may be criticized because they may simply differentiate products thatare not really different, as in the case of drugs that are identical with the brand-name drug selling at amuch higher price than the generic drug.Questions for Review1. The three attributes of monopolistic competition are: (1) there are many sellers; (2) each sellerproduces a slightly different product; and (3) firms can enter or exit the market without restriction.Monopolistic competition is like monopoly because firms face a downward-sloping demand curve, soprice exceeds marginal cost. Monopolistic competition is like perfect competition because, in the longrun, price equals average total cost, as free entry and exit drive economic profit to zero.2. In Figure 2, a firm has demand curve D1 and marginal-revenue curve MR1. The firm is making profitsbecause at quantity Q1, price (P1) is above average total cost (ATC). Those profits induce other firmsto enter the industry, causing the demand curve to shift to D2 and the marginal-revenue curve to shiftto MR2. The result is a decline in quantity to Q2, at which point the price (P2) equals average total cost (ATC), so profits are now zero.Figure 23. Figure 3 shows the long-run equilibrium in a monopolistically competitive market. Price equalsaverage total cost. Price is above marginal cost.Figure 34. Because, in equilibrium, price is above marginal cost, a monopolistic competitor produces too littleoutput. But this is a hard problem to solve because: (1) the administrative burden of regulating the large number of monopolistically competitive firms would be high; and (2) the firms are earning zero economic profits, so forcing them to price at marginal cost means that firms would lose money unless the government subsidized them.5. Advertising might reduce economic well-being because it manipulates people's tastes and impedescompetition by making products appear more different than they really are. But advertising might increase economic well-being by providing useful information to consumers and fosteringcompetition.6. Advertising with no apparent informational content might convey information to consumers if itprovides a signal of quality. A firm will not be willing to spend much money advertising a low-qualitygood, but may be willing to spend significantly more to advertise a high-quality good.7. The two benefits that might arise from the existence of brand names are: (1) brand names provideconsumers information about quality when quality cannot be easily judged in advance; and (2) brandnames give firms an incentive to maintain high quality to maintain the reputation of their brandnames.Quick Check Multiple Choice1. b2. d3. a4. d5. a6. cProblems and Applications1. a. Tap water is a monopoly because there is a single seller of tap water to a household .b. Bottled water is a monopolistically competitive market. There are many sellers of bottled water,but each firm tries to differentiate its own brand from the rest.c. The cola market is an oligopoly. There are only a few firms that control a large portion of themarket.d. The beer market is an oligopoly. There are only a few firms that control a large portion of themarket.2. a. The market for wooden #2 pencils is perfectly competitive because pencils by any manufacturerare identical and there are a large number of manufacturers.b. The market for copper is perfectly competitive, because all copper is identical and there are alarge number of producers.c. The market for local electricity service is monopolistic because it is a natural monopoly—it ischeaper for one firm to supply all the output.d. The market for peanut butter is monopolistically competitive because different brand namesexist with different quality characteristics.e. The market for lipstick is monopolistically competitive because lipstick from different firmsdiffers slightly, but there are a large number of firms that can enter or exit without restriction.3. a. A firm in monopolistic competition sells a differentiated product from its competitors.b. A firm in monopolistic competition has marginal revenue less than price.c. Neither a firm in monopolistic competition nor in perfect competition earns economic profit inthe long run.d. A firm in perfect competition produces at the minimum average total cost in the long run.e. Both a firm in monopolistic competition and a firm in perfect competition equate marginalrevenue and marginal cost.f. A firm in monopolistic competition charges a price above marginal cost.4. a. Both a firm in monopolistic competition and a monopoly firm face a downward-sloping demandcurve.b. Both a firm in monopolistic competition and a monopoly firm have marginal revenue that is lessthan price.c. A firm in monopolistic competition faces the entry of new firms selling similar products.d. A monopoly firm earns economic profit in the long run.e. Both a firm in monopolistic competition and a monopoly firm equate marginal revenue andmarginal cost.f. Neither a firm in monopolistic competition nor a monopoly firm produces the socially efficientquantity of output.5. a. The firm is not maximizing profit. For a firm in monopolistic competition, price is greater thanmarginal revenue. If price is below marginal cost, marginal revenue must be less than marginalcost. Thus, the firm should reduce its output to increase its profit.b. The firm may be maximizing profit if marginal revenue is equal to marginal cost. However, thefirm is not in long-run equilibrium because price is less than average total cost. In this case, firms will exit the industry and the demand facing the remaining firms will rise until economic profit is zero.c. The firm is not maximizing profit. For a firm in monopolistic competition, price is greater thanmarginal revenue. If price is equal to marginal cost, marginal revenue must be less than marginal cost. Thus, the firm should reduce its output to increase its profit.d. The firm could be maximizing profit if marginal revenue is equal to marginal cost. The firm is inlong-run equilibrium because price is equal to average total cost. Therefore, the firm is earningzero economic profit.6. a. Figure 4 illustrates the market for Sparkle toothpaste in long-run equilibrium. The profit-maximizing level of output is Q M and the price is P M.Figure 4b. Sparkle's profit is zero, because at quantity Q M, price equals average total cost.c. The consumer surplus from the purchase of Sparkle toothpaste is areas A + B. The efficient levelof output occurs where the demand curve intersects the marginal-cost curve, at Q C. Thedeadweight loss is area C, the area above marginal cost and below demand, from Q M to Q C.d. If the government forced Sparkle to produce the efficient level of output, the firm would losemoney because average total cost would exceed price, so the firm would shut down. If thathappened, Sparkle's customers would earn no consumer surplus.7. a. As N rises, the demand for each firm’s product falls. As a result, each firm’s demand curve willshift left.b. The firm will produce where MR = MC:100/N– 2Q = 2QQ = 25/Nc. 25/N = 100/N–PP = 75/Nd. Total revenue = P Q = 75/N 25/N = 1875/N2Total cost = 50 + Q2 = 50 + (25/N)2 = 50 + 625/N2Profit = 1875/N2– 625/N2– 50 = 1250/N2– 50e. In the long run, profit will be zero. Thus:1250/N2– 50 = 01250/N2 = 50N = 58. Figure 5 shows the cost, marginal revenue and demand curves for the firm under both conditions.Figure 5a. The price will fall from P MC to the minimum average total cost (P C) when the market becomesperfectly competitive.b. The quantity produced by a typical firm will rise to Q C, which is at the efficient scale of output.c. Average total cost will fall as the firm increases its output to the efficient scale.d. Marginal cost will rise as output rises. Marginal cost is now equal to price.e. Profit will not change. In either case, the market will move to long-run equilibrium where allfirms will earn zero economic profit.9. a. A family-owned restaurant would be more likely to advertise than a family-owned farm becausethe output of the farm is sold in a perfectly competitive market, in which there is no reason toadvertise, while the output of the restaurant is sold in a monopolistically competitive market.b. A manufacturer of cars is more likely to advertise than a manufacturer of forklifts because thereis little difference between different brands of industrial products like forklifts, while there aregreater perceived differences between consumer products like cars. The possible return toadvertising is greater in the case of cars than in the case of forklifts.c. A company that invented a very comfortable razor is likely to advertise more than a companythat invented a less comfortable razor that costs the same amount to make because thecompany with the very comfortable razor will get many repeat sales over time to cover the cost of the advertising, while the company with the less comfortable razor will not.10. a. Figure 6 shows Sleek’s demand, marginal-revenue, marginal-cost, and average-total-cost curves.The firm will maximize profit at an output level of Q * and a price of P *. The shaded are shows the firm’s profits.Figure 6b. In the long run, firms will enter, shifting the demand for Sleek’s product to the left. Its price andoutput will fall. Firms will enter until profits are equal to zero (as shown in Figure 7).Figure 7c. As consumers become more focused on the stylistic differences in brands, they will be lessfocused on price. This will make the demand for each firm’s products more price inelastic. The demand curves may become relatively steeper, allowing Sleek to charge a higher price. If these stylistic features cannot be copied, they may serve as a barrier to entry and allow Sleek to earn profit in the long run.d. A firm in monopolistic competition produces where marginal revenue is greater than zero. Thismeans that firm must be operating on the elastic portion of its demand curve.。
第十一章公共物品和共有资源复习题1．解释一种物品有“排他性”的含义。
解释一种物品有“竞争性”的含义。
比萨饼有排他性吗?有竞争性吗?答：一种物品具有“排他性”是指可以阻止一个人使用一种物品时该物品的特性。
一种物品有竞争性是指一个人使用一种物品减少其他人使用该物品的特性。
比萨饼有排他性，只要不卖给某人比萨饼就可以阻止他使用。
比萨饼也有竞争性，一个人多吃一块比萨饼，会使其他人少享受一块。
2．给公共物品下定义并举出一个例子。
私人市场本身能提供这种物品吗?并解释之。
答：公共物品是既无排他性又无竞争性的物品，私人市场本身不能提供这种物品。
公共物品没有排他性，因此，无法对公共物品的使用者收费，在私人提供这种物品时就存在搭便车的激励，从而使私人提供者无利可图。
3．什么是公共物品的成本一收益分析?为什么它是重要的?进行这种分析困难吗?答：公共物品的成本一收益分析是提供一种公共物品的社会成本和社会收益比较的研究。
只有比较提供一种公共物品的成本与收益，政府才能决定是否值得提供这种公共物品。
公共物品的成本一收益分析是一项艰苦的工作。
因为所有的人都可以免费使用一种公共物品，没有判断这种公共物品价值的价格。
简单地问人们，他们对一种公共物品的评价是多少是不可靠的。
那些受益于该公共物品的人有夸大他们的利益的激励。
那些受害于该公共物品的人有夸大他们成本的激励。
4．给共有资源下定义并举出一个例子。
没有政府干预，人们使用这种物品会太多还是太少?为什么?答：共有资源是有竞争性但无排他性的物品。
没有政府干预，人们使用这种物品会太多。
因为不能向使用共有资源的人收费，而且，一个人对共有资源的使用会减少其他人的使用，所以，共有资源往往被过度使用。
问题与应用1．本书认为公共物品和共有资源都涉及外部性。
A．与公共物品相关的外部性一般是正的还是负的?用例子来回答。
自由市场的公共物品量一般是大于还是小于有效率的数量?答：与公共物品相关的外部性一般是负的。
曼昆《经济学原理（微观经济学分册）》（第6版）第15章垄断复习笔记跨考网独家整理最全经济学考研真题，经济学考研课后习题解析资料库，您可以在这里查阅历年经济学考研真题，经济学考研课后习题，经济学考研参考书等内容，更有跨考考研历年辅导的经济学学哥学姐的经济学考研经验，从前辈中获得的经验对初学者来说是宝贵的财富，这或许能帮你少走弯路，躲开一些陷阱。
以下内容为跨考网独家整理，如您还需更多考研资料，可选择经济学一对一在线咨询进行咨询。
一、垄断产生的原因垄断企业是指一个没有相似替代品的产品的唯一卖者的企业。
垄断产生的基本原因是进入壁垒：垄断企业能在其市场上保持唯一卖者的地位，是因为其他企业不能进入市场并与之竞争。
进入壁垒有三个主要形成原因：第一，垄断资源：生产所需要的关键资源由单个企业所拥有；第二，政府管制：政府给予单个企业排他性地生产某种物品或劳务的权利；第三，生产流程：某个企业能以低于大量生产者的成本生产产品。
1．垄断资源垄断产生的最简单方法是单个企业拥有一种关键的资源。
垄断企业比竞争市场上任何一家企业有大得多的市场势力。
即使产品边际成本很低，垄断企业也可以利用市场势力也可以制定极高的价格。
虽然关键资源的排他性所有权是垄断的一个潜在起因，但实际上垄断很少产生于这种原因。
现实经济如此巨大，且资源由许多人拥有。
由于许多物品可以在国际上交易，它们的市场的自然范围往往很广泛。
因此，拥有没有相近替代品资源的企业的例子很少。
2．创造的垄断在许多情况下，垄断的产生是因为政府给予一个人或一个企业排他性地出售某种物品或劳务的权利，有时垄断产生于想成为垄断者的人的政治影响，还有些时候，政府也会出于公共利益而赋予某种垄断的权利。
专利法和版权法是两个重要的例子。
由于这些法律使一个生产者成为垄断者，所以也就使其价格高于竞争市场上的价格。
通过允许这些垄断生产者收取较高价格并赚取较多利润，这些法律也鼓励了一些合意的行为。
有关专利和版权的法律既有利益也有成本。
第十一章公共物品和共有资源复习题1．解释一种物品有“排他性”的含义。
解释一种物品有“竞争性”的含义。
比萨饼有排他性吗?有竞争性吗?答：一种物品具有“排他性”是指可以阻止一个人使用一种物品时该物品的特性。
一种物品有竞争性是指一个人使用一种物品减少其他人使用该物品的特性。
比萨饼有排他性，只要不卖给某人比萨饼就可以阻止他使用。
比萨饼也有竞争性，一个人多吃一块比萨饼，会使其他人少享受一块。
2．给公共物品下定义并举出一个例子。
私人市场本身能提供这种物品吗?并解释之。
答：公共物品是既无排他性又无竞争性的物品，私人市场本身不能提供这种物品。
公共物品没有排他性，因此，无法对公共物品的使用者收费，在私人提供这种物品时就存在搭便车的激励，从而使私人提供者无利可图。
3．什么是公共物品的成本一收益分析?为什么它是重要的?进行这种分析困难吗?答：公共物品的成本一收益分析是提供一种公共物品的社会成本和社会收益比较的研究。
只有比较提供一种公共物品的成本与收益，政府才能决定是否值得提供这种公共物品。
公共物品的成本一收益分析是一项艰苦的工作。
因为所有的人都可以免费使用一种公共物品，没有判断这种公共物品价值的价格。
简单地问人们，他们对一种公共物品的评价是多少是不可靠的。
那些受益于该公共物品的人有夸大他们的利益的激励。
那些受害于该公共物品的人有夸大他们成本的激励。
4．给共有资源下定义并举出一个例子。
没有政府干预，人们使用这种物品会太多还是太少?为什么?答：共有资源是有竞争性但无排他性的物品。
没有政府干预，人们使用这种物品会太多。
因为不能向使用共有资源的人收费，而且，一个人对共有资源的使用会减少其他人的使用，所以，共有资源往往被过度使用。
问题与应用1．本书认为公共物品和共有资源都涉及外部性。
A．与公共物品相关的外部性一般是正的还是负的?用例子来回答。
自由市场的公共物品量一般是大于还是小于有效率的数量?答：与公共物品相关的外部性一般是负的。
例如：基础知识是一种公共物品，任何人都可以免费使用，并且一个人对它的使用不会减少其他人的使用。
由于无法向基础知识的使用者收费，就会减少对科学家从事基础性研究的激励。
B．与公有资源相关的外部性一般是正的还是负的?用例子来回答。
自由市场的公有资源使用，一般是大于还是小于有效率的使用?答：与共有资源相关的外部性一般是负的。
例如：牧民们在天然牧场上过度放牧，使草场生态平衡遭到破坏，草场退化。
自由市场中共有资源的使用一般大于有效率的数量。
因为共有资源的使用是免费的，而且一个人的使用会减少其他人的使用。
2．考虑你们当地政府提供的物品与劳务。
A．用(教材)图11－1中的分类解释下列每种物品属于哪个范畴：⊙警察保护⊙铲雪⊙教育⊙乡间道路⊙城市街道答：⊙警察保护属于自然垄断，因为它有排他性却无竞争性。
⊙铲雪属于自然垄断，因为它有排他性却无竞争性。
⊙教育，尤其是义务教育属于共有资源，因为它无排他性却有竞争性。
⊙乡间道路属于公共物品，因为它即无排他性又无竞争性。
⊙城市道路属于共有资源，因为它无排他性却有竞争性。
B．为什么你认为政府提供了不是公共物品的东西?答：即使政府提供的物品和劳务不收费，也不能避免该种物品或劳务有竞争性。
例如城市道路，它一般是拥挤的，人们使用它不收费，但多一个人行走，就会使他人觉得更拥挤。
无排他性却有竞争性的物品是共有资源，不是公共物品。
而且，政府提供的某些物品或劳务可以不通过收费产生排他性。
如警察保护，只要警察对某个犯罪行为袖手旁观，就会使被害人不能享受这种劳务。
这种有排他性却无竞争性的物品不是公共物品，而是自然垄断。
3．查理喜欢看本地公共电视台的电视节目，但在电视台筹集运营资金的时候，他从不给一点钱支持电视台。
A．经济学家把查理称为什么名称?答：经济学家把查理称作“搭便车者”。
B．政府如何能解决像查理这样的人引起的问题?答：政府通过向查理们征税获取资金，用这些钱对电视台进行补贴。
C．你认为私人市场有解决这个问题的方法吗?如何把有线电视台的存在改变为公共电视台?答：我认为私人市场有解决这个问题的方法。
可以把这个公共电视台变成有线电视台，只有缴费的人才能开通该有线电视。
如果把有线电视台的存在改变为公共电视台，只有通过政府向当地居民征税，再用税收收入来补贴公共电视台。
4．本书认为私人企业没有从事基础研究的有效率数量。
A．解释为什么是这样。
在你的回答中，把基础研究划人(教材)图11－1所示的类型中的某一类。
答：基础研究的成果不具有产权，任何人都可以免费使用，而且不具有竞争性。
它是一种公共物品，私人企业没有提供的激励。
B．美国政府对这个问题的反应是采取了哪一类政策?答：美国政府采取了由国家出资进行基础科学研究的政策。
政府用税收收入开设研究机构，或对私人研究机构进行资助，开展基础科学研究。
C．人们往往认为，这种政策提高了美国生产者相对于外国企业的技术能力。
这种观点与你在(A)中对基础研究的分类一致吗?(提示：排他性是否能适用于一种公共物品的某些潜在受益者而不适用于其他人?) 答：这种观点与基础科学研究是公共物品的分类不矛盾。
因为任何事物都是相对的，公共物品的排他性也是如此。
基础科学研究成果在美国国内使用是没有排他性的。
但在国际领域，美国政府为了保护自己的研究成果不被对手国家使用，可以采取一系列相关措施，使某项研究成果对外保密，使美国生产者的生产能力相对高于外国同类企业。
5．为什么在大多数高速公路边都有垃圾，而在人们的院子里却很少呢?答：因为高速公路旁边的环境是共有资源，共有资源没有排他性，人们会随意使用。
同时，共有资源有竞争性，人们在使用时会产生负外部性，但没有人考虑负外部性，因此大多数高速公路旁都有垃圾。
而人们院子里的环境是私人物品，有排他性和竞争性。
人们在使用时要比较使用的成本和收益，因此自家院里的垃圾就很少。
6．华盛顿特区地铁系统在上下班高峰期的收费高于一天中的其他时间。
为什么应该这样做?答：因为地铁系统中的拥挤是一种负外部性。
上下班高峰期比平时拥挤得多，这时的外部性远远大于平时，解决这种外部性的有效方法是在上下班高峰期高收费。
这种高收费会激励乘地铁者改变时间表或使用别的交通工具上下班，以便减少付出的费用。
这样就可以减少上下班高峰时的外部性。
7．美国木材公司在公共拥有的土地上砍伐了许多树，在私人拥有的土地上也砍伐了许多树。
讨论在没有政府干预的情况下。
每一种类型的土地上伐木业的效率如何。
你认为政府应该如何管制公有土地上的伐木业?类似的管制应该使用于私人拥有的土地吗?答：在没有政府干预的情况下，在私人土地上伐木业的效率更高。
因为公有土地上的木材是共有资源，无排他性有竞争性，人们对共有资源常常会滥用，公有土地上的伐木量一定会超过有效率的数量。
私人土地上的树是私人物品，由供给和需求来决定它的市场采伐量，在自由市场条件下市场量一般是有效率的数量。
我认为政府可以对公有土地上的伐木业收费，每伐一棵树就必须向政府缴一定的费用。
也可以分配给每个木材公司一定量的可交易采伐许可证或者把公有土地分给私人。
类似的管制不适用于私人土地。
因为不存在外部性，私人的伐木业已经达到有效率的数量，采取管制就会产生无谓损失。
8．《经济学家》杂志的一篇文章(1994年3月19日)说：“在过去的十年间，富裕国家的鱼类已被捕捞到濒临灭绝的地步。
”该文继续分析这个问题，并讨论了可能的私人与政府的解决办法：A．“不要指责渔民过度捕捞。
当他们这样做时，他们是理性地行事的。
”在什么意义上说，“过度捕捞”对渔民来说是理性的?答：从渔民对公有资源的使用来说，过度捕捞对渔民来说是理性行事。
公用水域中的鱼类是共有资源，共有资源有竞争性无排他性。
渔民们为了使个人利益最大化，必然要尽量多地捕鱼。
B．“一个由责任和相互私利联系的社会可以靠自身管理一种共有资源。
”解释从原则上看这种管理能如何发挥作用，以及在现实世界中它面临什么障碍。
答：从原则上看，由于责任和相互私利联系，有关利益各方会坐下来进行商讨，在研究了各自利弊得失之后，达成一个对各方都有利的协议。
但在现实生活中，可能会由于利益主体过多使得达成协议十分困难，或者交易成本高于交易收益。
C．“直至1976年，世界大部分鱼的资源是向一切人开放的，要进行保护几乎是不可能的。
这时一项国际协议把(国家)的司法管辖权从12海里扩大到200海里。
”用产权的概念讨论这个协议如何减轻了问题的程度。
答：这项国际协议对渔民经常捕鱼的海域规定了产权。
产权使某些有价值的东西拥有了在法律上有权控制它的所有者。
所有者可以采取措施对使用这些有价值的东西的人进行管制，使资源配置更有效率。
对海域规定了产权，有管辖权的政府就可以对在该海域上捕鱼的渔民进行管制，在一定程度上制止滥捕鱼类。
D．该文提到，许多政府以一种鼓励增加捕鱼的方式对困难渔民进行补助。
这种政策如何鼓励过度捕捞的恶性循环?答：这种政策鼓励渔民过度捕捞鱼类。
由于捕捞过度，鱼类资源快速减少，渔民捕不到足够的鱼而更加贫穷。
因为贫穷，渔民渴望能够捕到更多的鱼，滥捕现象就会更加严重。
如此循环下去，鱼类最终会灭绝，渔民们最终会无以为生。
E．“只有在渔民相信他们长期排他性的捕鱼权得到保证时，他们才会向好农民管理土地一样，以一种目光长远的方式管理资源。
”为这种论述进行辩护。
答：给渔民们一种长期排他性的捕鱼权，等于使鱼类资源私有化。
鱼类资源成为私人物品，渔民们出于自身成本、利益的考虑，会以一种长远的目光来管理自己的鱼类资源。
F．还可以想出什么其他减少过度捕捞的政策?答：可以对捕捞鱼类征税，用税收把鱼类资源的捕捞控制在有效率的程度上。
还可以规定休渔期；规定渔民们使用的渔网的网眼大小，使小鱼可以存活下来。
9．在一个市场经济中，有关物品和劳务质量或作用的信息本身就是一种有价值的物品。
私人市场如何提供这种信息?你认为在提供这种信息中能使政府起作用的方法是什么?答：私人市场提供这种信息是要收费的，即使表面上不收费也是为了使自己的产品更好地销售出去。
有些信息，私人市场出于自身利益的考虑根本不愿提供。
有些信息对消费者来说是必不可少的，但对企业来说，免费提供这些信息又是不可能的。
政府在这种情况下，应采取强制披露措施，用法律手段规定企业必须无偿提供某些信息。
10．你认为互联网是一种公共物品吗?为什么是或不是?答：我认为互联网不是一种公共物品。
因为公共物品必须满足两个特征：无排他性和无竞争性，而互联网不具备这两种特征。
原因如下：公众在使用互联网时必须付费给互联网服务提供者(1SP)，在ISP提供的带宽容量很大而需求相对不足时，公众使用互联网时感觉不到它有排他性和竞争性，这时互联网像不拥挤的收费道路。
但是当上网者越来越多而带宽容量不够肘。
人们就会觉得上网的速度在变慢，这时互联网就具有竞争性和排他性两种特征，有点像拥挤的收费道路一样。
