5ELASTICITY AND ITS APPLICATION WHAT’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:
the meaning of the elasticity of demand.
what determines the elasticity of demand.
the meaning of the elasticity of supply.
what determines the elasticity of supply.
the concept of elasticity in three very different markets (the market for wheat, the market for oil, and the market for illegal drugs).
CONTEXT AND PURPOSE:
Chapter 5 is the second chapter of a three-chapter sequence that deals with supply and demand and how markets work. Chapter 4 introduced supply and demand. Chapter 5 shows how much buyers
and sellers respond to changes in market conditions. Chapter 6 will address the impact of government polices on competitive markets.
The purpose of Chapter 5 is to add precision to the supply-and-demand model. We introduce the concept of elasticity, which measures the responsiveness of buyers and sellers to changes in economic variables such as prices and income. The concept of elasticity allows us to make quantitative observations about the impact of changes in supply and demand on equilibrium prices and quantities.
KEY POINTS:
The price elasticity of demand measures how much the quantity demanded responds to changes in the price. Demand tends to be more elastic if close substitutes are available, if the good is a luxury rather than a necessity, if the market is narrowly defined, or if buyers have substantial time to react to a price change.
The price elasticity of demand is calculated as the percentage change in quantity demanded divided by the percentage change in price. If quantity demanded moves proportionately less than the price, then the elasticity is less than one, and demand is said to be inelastic.
If quantity demanded moves proportionately more than the price, then the elasticity is greater than one, and demand is said to be elastic.
Total revenue, the total amount paid for a good, equals the price of the good times the quantity sold. For inelastic demand curves, total revenue moves in the same direction as the price. For elastic demand curves, total revenue moves in the opposite direction as the price.
The income elasticity of demand measures how much the quantity demanded responds to
changes in consumers’ income. The cross-price elasticity of demand measures how much the quantity demanded of one good responds to the price of another good.
The price elasticity of supply measures how much the quantity supplied responds to changes in the price. This elasticity often depends on the time horizon under consideration. In most markets, supply is more elastic in the long run than in the short run.
The price elasticity of supply is calculated as the percentage change in quantity supplied divided by the percentage change in price. If quantity supplied moves proportionately less than the price, then the elasticity is less than one, and supply is said to be inelastic.
If quantity supplied moves proportionately more than the price, then the elasticity is greater than one, and supply is said to be elastic.
The tools of supply and demand can be applied in many different kinds of markets. This chapter uses them to analyze the market for wheat, the market for oil, and the market for illegal drugs.
CHAPTER OUTLINE:
I. The Elasticity of Demand
A. Definition of elasticity: a measure of the responsiveness of quantity demanded or
quantity supplied to one of its determinants.
B. The Price Elasticity of Demand and Its Determinants
1. Definition of price elasticity of demand: a measure of how much the quantity
demanded of a good responds to a change in the price of that good, computed as the
percentage change in quantity demanded divided by the percentage change in price.
2. Determinants of the Price Elasticity of Demand
a. Availability of Close Substitutes: the more substitutes a good has, the more
elastic its demand.
b. Necessities versus Luxuries: necessities are more price inelasti
c.
c. Definition of the market: narrowly defined markets (ice cream) have more
elastic demand than broadly defined markets (food).
d. Time Horizon: goods tend to have more elastic demand over longer time horizons.
C. Computing the Price Elasticity of Demand
1. Formula
2. Example: the price of ice cream rises by 10% and quantity demanded falls by 20%.
Price elasticity of demand = (20%)/(10%) = 2
3. Because there is an inverse relationship between price and quantity demanded (the
price of ice cream rose by 10% and the quantity demanded fell by 20%), the price elasticity of demand is sometimes reported as a negative number. We will ignore
the minus sign and concentrate on the absolute value of the elasticity.
D. The Midpoint Method: A Better Way to Calculate Percentage Changes and Elasticities
1. Because we use percentage changes in calculating the price elasticity of demand,
the elasticity calculated by going from one point to another on a demand curve
will be different from an elasticity calculated by going from the second point to
the first. This difference arises because the percentage changes are calculated
using a different base.
a. A way around this problem is to use the midpoint method.
b. Using the midpoint method involves calculating the percentage change in either
price or quantity demanded by dividing the change in the variable by the
midpoint between the initial and final levels rather than by the initial level
itself.
c. Example: the price rises from $4 to $6 and quantity demanded falls from 120 to
80.
% change in price = (6 ?4)/5 × 100 = 40%
% change in quantity demanded = (120 ? 80)/100 x 100 = 40%
price elasticity of demand = 40/40 = 1
E. The Variety of Demand Curves
1. Classification of Elasticity
a. When the price elasticity of demand is greater than one, demand is defined to
be elastic.
b. When the price elasticity of demand is less than one, the demand is defined to
be inelastic.
c. When the price elasticity of demand is equal to one, the demand is said to have
unit elasticity.
2. In general, the flatter the demand curve that passes through a given point, the
more elastic the demand.
3. Extreme Cases
a. When the price elasticity of demand is equal to zero, the demand is perfectly
inelastic and is a vertical line.
b. When the price elasticity of demand is infinite, the demand is perfectly
elastic and is a horizontal line.
4. FYI: A Few Elasticities from the Real World
F. Total Revenue and the Price Elasticity of Demand
1. Definition of total revenue: the amount paid by buyers and received by sellers of
a good, computed as the price of the good times the quantity sold.
2. If demand is inelastic, the percentage change in price will be greater than the
percentage change in quantity demanded.
a. If price rises, quantity demanded falls, and total revenue will rise (because
the increase in price will be larger than the decrease in quantity demanded).
b. If price falls, quantity demanded rises, and total revenue will fall (because
the fall in price will be larger than the increase in quantity demanded).
3. If demand is elastic, the percentage change in quantity demanded will be greater
than the percentage change in price.
a. If price rises, quantity demanded falls, and total revenue will fall (because
the increase in price will be smaller than the decrease in quantity demanded).
b. If price falls, quantity demanded rises, and total revenue will rise (because
the fall in price will be smaller than the increase in quantity demanded).
4. If demand is unit elastic, the percentage change in price will be equal to the
percentage change in quantity demanded.
a. If price rises, quantity demanded falls, and total revenue will remain the same
(because the increase in price will be equal to the decrease in quantity
demanded).
b. If price falls, quantity demanded rises, and total revenue will remain the same
(because the fall in price will be equal to the increase in quantity demanded).
G. Elasticity and Total Revenue along a Linear Demand Curve
1. The slope of a linear demand curve is constant, but the elasticity is not.
a. At points with a low price and a high quantity demanded, demand is inelastic.
b. At points with a high price and a low quantity demanded, demand is elasti
c.
2. Total revenue also varies at each point along the demand curve.
H. Other Demand Elasticities
1. Definition of income elasticity of demand: a measure of how much the quantity
demanded of a good responds to a change in consumers’ income, computed as the percentage change in quantity demanded divided by the percentage change in income.
a. Formula
Figure 4 Note that when demand is elastic and price falls, total revenue rises. Also
point out that once demand is inelastic, any further decrease in price
% change in quantity demanded Income elasticity of demand =
% change in income
b. Normal goods have positive income elasticities, while inferior goods have
negative income elasticities.
ALTERNATIVE CLASSROOM EXAMPLE:
John’s income rises from $20,000 to $22,000 and the quantity of hamburger he buys
each week falls from 2 pounds to 1 pound.
% change in quantity demanded = (1?2)/ x 100 = %
% change in income = (22,000 ?20,000)/21,000 x 100 = %
c. Necessities tend to have small income elasticities, while luxuries tend to have
large income elasticities.
2. Definition of cross-price elasticity of demand: a measure of how much the quantity
demanded of one good responds to a change in the price of another good, computed
as the percentage change in the quantity demanded of the first good divided by the percentage change in the price of the second good.
a. Formula
b. Substitutes have positive cross-price elasticities, while complements have
negative cross-price elasticities.
ALTERNATIVE CLASSROOM EXAMPLE:
The price of apples rises from $ per pound to $ per pound. As a result, the
quantity of oranges demanded rises from 8,000 per week to 9,500.
% change in quantity of oranges demanded = (9,500 ? 8,000)/8,750 x 100 = %
% change in price of apples = ? / x 100 = 40%
II. The Elasticity of Supply
A. The Price Elasticity of Supply and Its Determinants
1. Definition of price elasticity of supply: a measure of how much the quantity
supplied of a good responds to a change in the price of that good, computed as the
percentage change in quantity supplied divided by the percentage change in price.
2. Determinants of the Price Elasticity of Supply
a. Flexibility of sellers: goods that are somewhat fixed in supply (beachfront
property) have inelastic supplies.
b. Time horizon: supply is usually more inelastic in the short run than in the
long run.
B. Computing the Price Elasticity of Supply
1. Formula
2. Example: the price of milk increases from $ per gallon to $ per gallon and the
quantity supplied rises from 9,000 to 11,000 gallons per month.
% change in price = –/ × 100 = 10%
% change in quantity supplied = (11,000 –9,000)/10,000 × 100 = 20%
Price elasticity of supply = (20%)/(10%) = 2
C. The Variety of Supply Curves
1. In general, the flatter the supply curve that passes through a given point, the
more elastic the supply.
2. Extreme Cases
a. When the elasticity is equal to zero, the supply is said to be perfectly
inelastic and is a vertical line.
b. When the elasticity is infinite, the supply is said to be perfectly elastic and
is a horizontal line.
3. Because firms often have a maximum capacity for production, the elasticity of
supply may be very high at low levels of quantity supplied and very low at high
levels of quantity supplied.
III. Three Applications of Supply, Demand, and Elasticity
A. Can Good News for Farming Be Bad News for Farmers
1. A new hybrid of wheat is developed that is more productive than those used in the
past. What happens
2. Supply increases, price falls, and quantity demanded rises.
3. If demand is inelastic, the fall in price is greater than the increase in quantity
demanded and total revenue falls.
4. If demand is elastic, the fall in price is smaller than the rise in quantity
demanded and total revenue rises.
5. In practice, the demand for basic foodstuffs (like wheat) is usually inelastic.
a. This means less revenue for farmers.
b. Because farmers are price takers, they still have the incentive to adopt the
new hybrid so that they can produce and sell more wheat.
c. This may help explain why the number of farms has declined so dramatically over
the past two centuries.
d. This may also explain why some government policies encourage farmers to
decrease the amount of crops planted.
B. Why Did OPEC Fail to Keep the Price of Oil High
Figure 8
Short Run Long Run
1. In the 1970s and 1980s, OPEC reduced the amount of oil it was willing to supply to
world markets. The decrease in supply led to an increase in the price of oil and a decrease in quantity demanded. The increase in price was much larger in the short run than the long run. Why
2. The demand and supply of oil are much more inelastic in the short run than the
long run. The demand is more elastic in the long run because consumers can adjust to the higher price of oil by carpooling or buying a vehicle that gets better
mileage. The supply is more elastic in the long run because non-OPEC producers
will respond to the higher price of oil by producing more.
C. Does Drug Interdiction Increase or Decrease Drug-Related Crime
1. The federal government increases the number of federal agents devoted to the war
on drugs. What happens
a. The supply of drugs decreases, which raises the price and leads to a reduction
in quantity demanded. If demand is inelastic, total expenditure on drugs (equal
to total revenue) will increase. If demand is elastic, total expenditure will
fall.
b. Thus, because the demand for drugs is likely to be inelastic, drug-related
crime may rise.
2. What happens if the government instead pursued a policy of drug education
a. The demand for drugs decreases, which lowers price and quantity supplied. Total
expenditure must fall (because both price and quantity fall).
b. Thus, drug education should not increase drug-related crime.
SOLUTIONS TO TEXT PROBLEMS:
Quick Quizzes
1. The price elasticity of demand is a measure of how much the quantity demanded of a
good responds to a change in the price of that good, computed as the percentage change in quantity demanded divided by the percentage change in price.
When demand is inelastic (a price elasticity less than 1), a price increase raises
total revenue, and a price decrease reduces total revenue. When demand is elastic (a price elasticity greater than 1), a price increase reduces total revenue, and a price decrease increases total revenue. When demand is unit elastic (a price elasticity equal to 1), a change in price does not affect total revenue.
2. The price elasticity of supply is a measure of how much the quantity supplied of a
good responds to a change in the price of that good, computed as the percentage change in quantity supplied divided by the percentage change in price.
The price elasticity of supply might be different in the long run than in the
short run because over short periods of time, firms cannot easily change the sizes Figure 9
(a) Drug Interdiction (b) Drug Education
of their factories to make more or less of a good. Thus, in the short run, the
quantity supplied is not very responsive to the price. However, over longer
periods, firms can build new factories, expand existing factories, close old
factories, or they can enter or exit a market. So, in the long run, the quantity
supplied can respond substantially to a change in price.
3. A drought that destroys half of all farm crops could be good for farmers (at least
those unaffected by the drought) if the demand for the crops is inelastic. The
shift to the left of the supply curve leads to a price increase that will raise
total revenue if the price elasticity of demand is less than 1.
No one farmer would have an incentive to destroy her crops in the absence of a
drought because she takes the market price as given. Only if all farmers
destroyed a portion of their crops together, for example through a government
program, would this plan work to make farmers better off.
Questions for Review
1. The price elasticity of demand measures how much quantity demanded responds to a
change in price. The income elasticity of demand measures how much quantity
demanded responds to changes in consumers' income.
2. The determinants of the price elasticity of demand include the availability of
close substitutes, whether the good is a necessity or a luxury, the breadth of the
definition of the market, and the time horizon. Goods with close substitutes have
greater elasticities, luxury goods have greater price elasticities than
necessities, goods in more narrowly defined markets have greater elasticities, and
the elasticity of demand is greater the longer the time horizon.
3. An elasticity greater than one means that demand is elastic. When the elasticity
is greater than one, the percentage change in quantity demanded exceeds the
percentage change in price. When the elasticity equals zero, demand is perfectly inelastic. There is no change in quantity demanded when there is a change in price.
4. Figure 1 presents a supply-and-demand diagram, showing the equilibrium price, P,
the equilibrium quantity, Q, and the total revenue received by producers. Total revenue equals the equilibrium price times the equilibrium quantity, which is the area of the rectangle shown in the figure.
Figure 1
5. If demand is elastic, an increase in price reduces total revenue. With elastic
demand, the quantity demanded falls by a greater percentage than the price rises.
As a result, total revenue moves in the opposite direction as the price. Thus, if price rises, total revenue falls.
6. A good with income elasticity less than zero is called an inferior good because as
income rises, the quantity demanded declines.
7. The price elasticity of supply is calculated as the percentage change in quantity
supplied divided by the percentage change in price. It measures how much quantity supplied responds to changes in price.
8. If a fixed quantity of a good is available and no more can be made, the price
elasticity of supply is zero. Regardless of the percentage change in price, there
will be no change in the quantity supplied.
9. Destruction of half of the fava bean crop is more likely to hurt fava bean farmers
if the demand for fava beans is very elastic. Destruction of half of the crop
causes the supply curve to shift to the left resulting in a higher price of fava
beans. When demand is very elastic, an increase in price leads to a decrease in
total revenue because the decrease in quantity demanded outweighs the increase in
price.
Quick Check Multiple Choice
1. a
2. b
3. d
4. c
5. a
6. c
Problems and Applications
1. a. Mystery novels have more elastic demand than required textbooks because mystery
novels have close substitutes and are a luxury good, while required textbooks
are a necessity with no close substitutes. If the price of mystery novels were
to rise, readers could substitute other types of novels, or buy fewer novels
altogether. But if the price of required textbooks were to rise, students would
have little choice but to pay the higher price. Thus, the quantity demanded of
required textbooks is less responsive to price than the quantity demanded of
mystery novels.
b. Beethoven recordings have more elastic demand than classical music recordings
in general. Beethoven recordings are a narrower market than classical music
第三章 6．下表描述了Baseballia国两个城市的生产可能性： 一个工人每小时生产的红补袜子量一个工人每小时生产的白袜子量 A．没有贸易，波士顿一双白袜子价格（用红袜子表示）是多少芝加哥11双白袜子价格是多少答：没有贸易时，波士顿1 双白袜子价格是1 双红袜子，芝加哥1 双白袜子价格是2 双红袜子。B．在每种颜色的袜子生产上，哪个城市有绝对优势哪个城市有比较优势 答：波士顿在生产红、白袜子上都有绝对优势。波士顿在生产白袜子上有比较优势，芝加哥在生产红袜子上有比较优势。 C．如果这两个城市相互交易，两个城市将分别出口哪种颜色的袜子 答：如果它们相互交易，波士顿将出口白袜子，而芝加哥出口红袜子。 D．可以进行交易的价格范围是多少 答：白袜子的最高价格是2 双红袜子，最低价格是1 双红袜子。红袜子的最高价格是1 双白袜子，最低价格是1／2 双白袜子。 7．假定一个美国工人每年能生产100件衬衣或20台电脑，而一个中国工人每年能生产100件衬衣或10台电脑。 A．画出这两个国家的生产可能性边界。假定没有贸易，每个国家的工人各用一半的时间生产两种物品，在你的图上标出这一点。 答：两个国家的生产可能性边界如图3 一4 所示。如果没有贸易，一个美国工人把一半的时间用于生产每种物品，则能生产50 件衬衣、10 台电脑；同样，一个中国工人则能生产50 件衬衣、5 台电脑。
图3 一4 生产可能性边界 B．如果这两个国家进行贸易，哪个国家将出口衬衣举出一个具体的数字例子，并在你的图上标出。哪一个国家将从贸易中获益解释原因。 答：中国将出口衬衣。对美国而言，生产一台电脑的机会成本是5 件衬衣，而生产一件衬衣的机会成本为1/5 台电脑。对中国而言，生产一台电脑的机会成本是10 件衬衣，而生产一件衬衣的机会成本为1/10 台电脑。 因此，美国在生产电脑上有比较优势，中国在生产衬衣上有比较优势，所以中国将出口衬衣。 衬衣的价格在1/5 到1/10 台电脑之间。两个国家都会从贸易中获益。例如，衬衣的价格为1/8 台电脑，换言这，中国出口8 件衬衣换回1 台电脑。中国专门生产衬衣（100 件），并出口其中的8 件，这样就有92 件衬衣和换回的1 台电脑。而没有贸易时，92 件衬衣和1 台电脑在中国是不可能得到的产出。美国专门生产电脑（20 台）并向中国出口其中的1 台换取8 件衬衣。这样，美国最后就有19 台电脑和8 件衬衣，这也是没有贸易时美国不可 能得到的产出。由此可见，贸易使中国和美国所能消费的产品增加，两国都获益了。 C．解释两国可以交易的电脑价格（用衬衣衡量）是多少。 答：一台电脑的价格将在5 到10 件衬衣之间。如果电脑价格低于5 件衬衣，美国将不会出口，因为在美国一件衬衣的机会成本为1/5 台电脑。如果电脑的价格高于10 件衬衣，中国将不会进口，因为在中国一台电脑的机会成本是10 件衬衣。 D．假设中国的生产率赶上了美国，因此，一个中国工人每年可以生产100件衬衣或20台电脑。你预期这时的贸易形式会是什么样的。中国生产率的这种进步将如何影响两国居民的经济福利 答：此时，中美双方将同时生产两种商品，然后进行贸易，不过此时的贸易被称为水平贸易，即生产率大致相同的两个国家进行的贸易。而中国在提高生产率之前，两国进行的是垂直贸易。垂直
23章 微观经济学：研究家庭和企业如何做出决策，以及它们如何在市场上相互影响。 宏观经济学：研究整体经济现象，包括通货膨胀，失业和经济增长。 国内生产总值（GDP ）：在某一既定时期一个国家内生产的所有最终物品与劳务的市场价值。 消费：家庭除购买新住房之外用于物品与劳务的支出。 投资：用于资本设备、存货和建筑物的支出，包括家庭用于购买新住房的支出。 政府购买：地方、州和联邦政府用于物品与劳务的支出。 净出口：外国人对国内生产的物品的支出（出口）减国内居民对外国物品的支出（进口）。 名义GDP ：按现期价格评价的物品与劳务的生产。 真实GDP ：按不变价格评价的物品与劳务的生产。 GDP 平减指数：用名义GDP 与真实GDP 的比率乘以100计算的物价水平衡量指标。 100GDP GDP GDP ?=真实名义平减指数 %100GDP GDP -GDP ?=平减指数 第一年的平减指数第一年的平减指数第二年的第二年的通货膨胀率 24章 消费物价指数（CPI ）：普通消费者所购买的物品与劳务的总费用的衡量指标。 100?=基年一篮子的价格 的价格当年一篮子物品与劳务消费物价指数 通货膨胀率：从前一个时期以来物价指数变动的百分比。 %100CPI CPI -CPI ?=第一年第一年第二年第二年的通货膨胀率 生产物价指数：企业购买的一篮子物品与劳务的费用的衡量指标。 年的物价水平 今天的物价水平年美元的数量今天的美元的数量T T ?= 指数化：根据法律或协议按照通货膨胀的影响对美元数量的自动调整。 名义利率：通常公布的、未根据通货膨胀的影响校正的利率。 真实利率：根据通货膨胀的英雄校正过得利率。 25章 生产率：每单位劳动投入所生产的物品与劳务的数量。 物质资本：用于生产物品与劳务的设备和建筑物存量。 人力资本：工人通过教育、培训和经验而获得的知识与技能。 自然资源：由自然界提供的用于生产物品和劳务的投入，如土地、河流和矿藏。 技术知识：社会对生产物品与劳务的最好方法的了解。 收益递减：随着投入量的增加，每一单位额外投入得到的收益减少的特性。 追赶效应：开始时贫穷的国家倾向于比开始时富裕的国家增长更快的特征。 26章 金融体系：经济中促使一个人的储蓄与另一个人的投资相匹配的一组机构。 金融市场：储蓄者可以借以直接向借款者提供资金的金融机构。
144 WHAT’S NEW IN THE S EVENTH EDITION: A new In the News box on ―The Tax Debate ‖ has been added. LEARNING OBJECTIVES: By the end of this chapter, students should understand: how taxes reduce consumer and producer surplus. the meaning and causes of the deadweight loss from a tax. why some taxes have larger deadweight losses than others. how tax revenue and deadweight loss vary with the size of a tax. CONTEXT AND PURPOSE: Chapter 8 is the second chapter in a three-chapter sequence dealing with welfare economics. In the previous section on supply and demand, Chapter 6 introduced taxes and demonstrated how a tax affects the price and quantity sold in a market. Chapter 6 also described the factors that determine how the burden of the tax is divided between the buyers and sellers in a market. Chapter 7 developed welfare economics —the study of how the allocation of resources affects economic well-being. Chapter 8 combines the lessons learned in Chapters 6 and 7 and addresses the effects of taxation on welfare. Chapter 9 will address the effects of trade restrictions on welfare. The purpose of Chapter 8 is to apply the lessons learned about welfare economics in Chapter 7 to the issue of taxation that was addressed in Chapter 6. Students will learn that the cost of a tax to buyers and sellers in a market exceeds the revenue collected by the government. Students will also learn about the factors that determine the degree by which the cost of a tax exceeds the revenue collected by the government. 8 APPLICATION: THE COSTS OF TAXATION
Chapter 8 Application: The Costs of Taxation Test A 1. A tax levied on the buyers of a product shifts the a. demand curve upward or to the right. b. demand curve downward or to the left. c. supply curve upward or to the left. d. supply curve downward or to the right. ANSWER: b. demand curve downward or to the left. TYPE: M KEY1: D SECTION: 1 OBJECTIVE: 1 RANDOM: Y 2. When a tax is levied on a good a. buyers are worse off but sellers are not. b. sellers are worse off but buyers are not. c. neither buyers nor sellers are worse off. d. both buyers and sellers are worse off. ANSWER: d. both buyers and sellers are worse off. TYPE: M KEY1: D SECTION: 1 OBJECTIVE: 1 RANDOM: Y 3. When a tax on a good is enacted, a. sellers always bear the full burden of the tax. b. buyers always bear the full burden of the tax. c. buyers and sellers share the burden of the tax regardless of which party it is levied on. d. sellers bear the full burden if the tax is levied on them, but buyers bear the full burden if the tax is levied on them. ANSWER: c. buyers and sellers share the burden of the tax regardless of which party it is levied on. TYPE: M KEY1: C SECTION: 1 OBJECTIVE: 1 RANDOM: Y 4. A tax placed on a good a. causes the price of the good to fall. b. causes the size of the market for the good to shrink. c. affects buyers of the good, but not sellers. d. is usually borne entirely by the seller of the good. ANSWER: b. causes the size of the market for the good to shrink. TYPE: M KEY1: C SECTION: 1 OBJECTIVE: 1 RANDOM: Y 5. When a tax is levied on a good a. the market price falls because demand declines. b. the market price falls because supply falls. c. the market price rises because demand falls. d. a wedge is placed between the price buyers pay and the price sellers receiv e. ANSWER: d. a wedge is placed between the price buyers pay and the price sellers receive. TYPE: M KEY1: C SECTION: 1 OBJECTIVE: 1 RANDOM: Y
第 20 章货币制度 1、为什么银行不持有百分百的准备金？银行持有的准备金量和银行体系所创造的货币量 有什么关系？ 参考答案： 银行不持有百分百的准备金是因为把存款用于放贷并收取利息比持有全部存款更有利 可图。银行持有的准备金量和银行体系通过货币乘数所创造的货币量是相关的。银行的准备金率越低，货币乘数越大，所以银行存款的每一元钱可以创造更多的货币 2、考察以下情况如何影响经济的货币制度。 a、假设雅普岛的居民发现了一种制造石轮的简单方法。这种发现如何影响石轮作为货 币的有用性呢？并解释之。 b、假设美国某个人发现了一种仿造100 美元钞票的简单办法。这种发现将如何影响美 国的货币制度呢？并解释之。 参考答案： a、如果有一种制造石轮的简单方法，雅普岛上的居民就会制造多余的石轮，只要每个 石轮的货币价值大于制造它的成本。结果，人们会自己制造货币，于是就有太多的货币被制 造出来。最有可能的是，人们会停止接受石轮作为货币，而转向其他资产作为交换的媒介 b.如果美国有人发现了伪造百元面值美钞的简单方法，他们就会大量地生产这种假 钞，而降低百元美钞的价值，结果可能是转为使用另一种通货。 3、伯列戈瑞德州银行(BSB)有 2.5 亿美元存款，并保持10％的准备率。 a)列出 BSB的 T 账户。 b) 现在假设BSB的大储户从其账户中提取了1000 万美元现金。如果 BSB决定通过减 少其未清偿贷款量来恢复其准备率，说明它的新T 账户。 c) 解释 BSB的行动对其他银行有什么影响？ d) 为什么 BSB要采取 (b) 中所描述的行为是困难的？讨论BSB恢复其原来准备金率的 另一种方法。 参考答案： a. BSB的 T 账户如下： : 伯列戈瑞德州银行(BSB) 资产负债 准备金$25 million存款$250 million 贷款$225 million b.当 BSB的大储户提取了 1000 万美金现金，而 BSB通过减少其未清偿贷款量来恢复其 准备率，它的 T 账户如下：
WHAT’S NEW IN THE S EVENTH EDITION: A new Case Study on Left-Digit Bias has been added and a new In the News feature on "Can Brain Science Improve Economics" has been added. LEARNING OBJECTIVES: By the end of this chapter, students should understand: how to examine problems caused by asymmetric information. the market solutions to asymmetric information. why democratic voting systems may not represent the preferences of society. why people may not always behave as rational maximizers. CONTEXT AND PURPOSE: Chapter 22 is the last chapter in the microeconomics portion of the text. It is the second of two unrelated chapters that introduce students to advanced topics in microeconomics. These two chapters are intended to whet their appetites for further study in economics. The purpose of Chapter 22 is to give students a taste of three topics on the frontier of microeconomic research. The first topic addressed is asymmetric information , a situation when one person in an economic relationship has more relevant knowledge than the other person does. The second topic is political economy , the application of economic tools to the understanding of the functioning of government. The third topic addressed is behavioral economics , the introduction of psychology into the study of economic issues. 22 FRONTIERS OF MICROECONOMICS
第十二章税制的设计 复习题 1．在过去的几十年来，政府的增长比经济中的其他部分快还是慢? 答：在过去几十年间，政府的增长比经济中其他部分快。数据表明，美国经济中包括联邦、州和地方政府在内的政府收入在总收人中所占百分比的增长速度快于经济中其他部分。 2．美国联邦政府收入最重要的两个来源是什么? 答：美国联邦政府收入最重要的两个来源是个人收入所得税和用于社会保障的工薪税。 3．解释公司利润如何双重纳税。 答：当企业赚到利润时，它要按公司所得税交税；当企业用其利润向公司股东支付股息时，按个人所得税第二次交税。 4．为什么纳税人的税收负担大于政府得到的收入? 答：因为纳税人的税收负担除了向政府交纳的税收之外，还包括两种成本：一是税收改变了激励所引起的资源配置扭曲；二是遵守税法的管理负担。这两种成本没有政府的收入作为补偿。因此，纳税人的税收负担大于政府得到的收入。 5．为什么一些经济学家支持对消费征税，而不是对收入征税? 答：因为对收入征税扭曲了对人们储蓄的激励，鼓励人们少储蓄。如果政府采取消费税，储蓄起来的全部收入在最后支出前都不征税，就不会扭曲人们的储蓄决策。 6．举出富有的纳税人应该比贫穷纳税人多纳税的两种观点。 答：这方面的观点有受益原则和能力纳税原则。 受益原则认为：人们应该根据他们从政府服务中得到的利益来纳税。通常富人从公共服务中受益多，他们应该多纳税。 能力纳税原则认为：应该根据一个人所能承受的负担来对这个人征税。显然，富人的财务承受能力强于穷人，富人应该多纳税。 7．什么是横向平等概念。为什么运用这个概念是困难的? 答：横向平等是指主张有相似支付能力的纳税人应该缴纳等量税收的思想。这一原则面临的问题是什么决定两个纳税人是相似的。每个纳税人在许多方面不同，为了评价税收是不是横向平等，必须决定哪些差别对纳税人的支付能力是相关的，哪些是不相关的。这些相关关系的确定是复杂而困难的。它不仅涉及经济学问题，还涉及价值观问题，很难说确定的结果是否公平。 8．说明支持与反对用单一税率取代现行税制的观点。 答：单一税率的支持者认为：(1)单一税率税将取消现行所得税的许多税收减免。通过用这种方法扩大税基，固定税能够降低大多数人面临的边际税率。税率越低意味着经济福利越大。因此，单一税率支持者声称，这种改变将扩大经济馅饼的规模。(2)由于单一税率税如此简单，所以，赋税的管理负担将大大降低。(3)由于所有纳税人都面临相同的边际税率，所以可以按收入来源而不是按得到收入的人来收税。这种额外的简单化也降低了管理成本。 (4)单一税率税将取代个人所得税和公司所得税。所有收入无论是来自工作中的劳动还是来自公司中拥有的股份，都按相同的边际税率一次性纳税。单一税率将消除目前对公司利润的双重征税，这就可以鼓励企业投资于新工厂和设备。(5)在为纳税计算收入时，允许企业扣除所有合法的经营支出，包括新投资品的支出。这种投资扣除使单一税率税更像消费税而不像所得税。结果，变为单一税率税将提高对投资的激励。 单一税率税的反对者认为：这种税很少注意纵向平等的目标。他们声称，单一税率税的累进性要小于现在的税制，而且，特别是它会把一些税收负担从富人身上转移到中产阶级身上。
曼昆经济学原理答案30—34
第十二篇短期经济波动 第三十一章总需求与总供给 复习题 1．写出当经济进入衰退时下降的两个宏观经济变量的名字。写出当经济进入衰退时上升的一个宏观经济变量的名字。 答：当经济进入衰退时，实际GDP和投资支出下降，失业率上升。 2．画出一个有总需求、短期总供给和长期 总供给的曲线的图。仔细地标出正确的轴。 答： 图31—1 经济的长期均衡 3．列出并解释总需求曲线向右下方倾斜的 三个原因。 答：为了理解总需求曲线向右下 方倾斜的原因，我们必须考察物价水平如何影响消费、投资和净出口的物品与劳务需求量。 (1)庇古的财富效应
物价水平下降使消费者感到更富裕，这又鼓励他们更多地支出，消费支出增加意味着物品与劳务的需求量更大。 (2)凯恩斯的利率效应 较低的物价水平降低了利率，鼓励了家庭和企业更多地支出于投资物品，从而增加了物品与劳务的需求量。 (3)蒙代尔——弗莱明汇率效应 当美国物价水平下降引起美国利率下降时，实际汇率贬值，而且这种贬值刺激了美国的净出口，从而增加了国外对美国物品与劳务的需求量。 由于这三个原因，总需求曲线向右下方倾斜。 4．解释为什么长期总供给曲线是垂线。 答：在长期中，一个经济的物品与劳务的供给取决于它资本与劳动的供给，以及用来把资本与劳动变为物品与劳务的生产技术。由于物价水平并不影响这些实际GDP的长期决定因素，所以长期总供给曲线是一条垂线，即经济的资本、劳动和技术决定了物品与劳务供给量，而且，无论物价水平如何变动，供给量都是相同的。
5．列出并解释为什么短期总供给曲线向右上方倾斜的三种理论。 答：在短期中，总供给曲线向右上方倾斜，也就是说，在一个一两年的时期中，经济中物价总水平的上升增加了物品与劳务的供给量，而物价水平下降倾向于减少物品与劳务供给量。什么因素引起物价水平与产量之间的正相关关系呢?宏观经济学家提出了三种理论说明短期总供给曲线的向右上方倾斜。在每一种理论中，一种特殊的市场不完全性引起经济中供给一方的短期状况与长期不同。虽然每一种理论在细节上不同，但它们具有共同的内容：当物价水平背离了人们预期的物价水平时，供给量就背离了其长期水平或“自然水平”。当物价水平高于预期水平时，产量就高于其自然率。当物价水平低于预期水平时，产量就低于其自然率。 (1)新古典的错觉理论 根据这种理论，物价总水平的变动会暂时误导供给者对他们出售其产品的市场发生的变动的看法。由于这些短期的错觉，供给者对物价水平的变动作出了反应，而这种反应引起了向右上方倾斜的总供给曲线。假设物价总水平降到低于
1 / 5 第20xx货币制度 1、为什么银行不持有百分百的准备金？银行持有的准备金量和银行体系所创造的货币量有什么关系？ 参考 答案： 银行不持有百分百的准备金是因为把存款用于放贷并收取利息 比持有全部存款更有利可图。银行持有的准备金量和银行体系通过货币乘数所创造的货币量是相关的。银行的准备金率越低，货币乘数越大，所以银行存款的每一元钱可以创造更多的货币 2、考察以下情况如何影响经济的货币制度。 a、假设雅普岛的居民发现了一种制造石轮的简单方法。这种发现如何影响石轮作为货币的有用性呢？并解释之。 b、假设美国某个人发现了一种仿造100美元钞票的简单办法。这种发现将如何影响美国的货币制度呢？并解释之。 参考 答案： a、如果有一种制造石轮的简单方法，雅普岛上的居民就会制造多余的石轮，只要每个石轮的货币价值大于制造它的成本。结果，人们会自己制造货币，于是就有太多的货币被制造出来。最有可能的是，人们会停止接受石轮作为货币，而转向其他资产作为交换的媒介
b.如果美国有人发现了伪造百元面值美钞的简单方法，他们就会大量地生产这种假钞，而降低百元美钞的价值，结果可能是转为使用另一种通货。 3、xx瑞德州银行(BSB)有 2.5亿美元存款，并保持10％的准备率。 2 / 5 a)列出BSB的T账户。 b)现在假设BSB的大储户从其账户中提取了1000万美元现金。如果BSB决定通过减少其未清偿贷款量来恢复其准备率，说明它的新T账户。 c)解释BSB的行动对其他银行有什么影响？ d)为什么BSB要采取(b)中所描述的行为是困难的？讨论BSB恢复其原来准备金率的另一种方法。 参考 答案： a. xx瑞德州银行(BSB) 资产 准备金 贷款 b.当BSB的大储户提取了1000万美金现金，而BSB通过减少其未清偿贷款量来恢复其准备率，它的T账户如下： $25 million存款
第一篇导言 第一章经济学十大原理 1．列举三个你在生活中面临的重要权衡取合的例子。 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。 4、为什么决策者应该考虑激励? 答：因为人们会对激励做出反应。如果政策改变了激励，它将使人们改变自己的行为，当决策者未能考虑到行为如何由于政策的原因而变化时．他们的政策往往会产生意想不到的效果。 5 为什么各国之间的贸易不像竞赛一样有赢家和输家呢? 答：因为贸易使各国可以专门从事自己最擅长的话动，并从中享有更多的各种各样的物品与劳务。通过贸易使每个国家可供消费的物质财富增加，经济状况变得更好。因此，各 个贸易国之间既是竞争对手，又是经济合作伙伴。在公平的贸易中是“双赢”或者“多赢” 的结果。 6．市场巾的那只“看不见的手”在做什么呢，答：市场中那只“看不见的手”就是商品价格，价格反映商品自身的价值和社会成本， 市场中的企业和家庭在作出买卖决策时都要关注价格。因此．他们也会不自觉地考虑自己行为的（社会）收益和成本。从而，这只“看不见的手”指引着干百万个体决策者在大多数情况下使社会福利趋向最大化。 7 解释市场失灵的两个主要原因，并各举出一个例子。答：市场失灵的主要原因是外部性和市场势力。外部性是一个人的行为对旁观者棉利的影响。当一个人小完全承担（或享受）他的行为所造成的成本（或收益）时，就会产生外部性。举例：如果一个人不承担他在公共场所吸烟的全部成本，他就会毫无顾忌地吸烟。在这种情况下，政府可以通过制定禁止在公共场所吸烟的规章制度来增加经济福利。 市场势力是指一个人（或一小群人）不适当地影响市场价格的能力。例如：某种商品的垄断生产者由于几乎不受市场竞争的影响，可以向消费者收取过高的垄断价格。在这种情况下，规定垄断者收取的价格有可能提高经济效率。 8．为什么生产率是重要的? 答：因为一国的生活水平取决于它生产物品与劳务的能力，而对这种能力的最重要的 衡量度就是生产率。生产率越高，一国生产的物品与劳务量就越多。 9 什么是通货膨胀，什么引起了通货膨胀? 答：通货膨胀是流通中货币量的增加而造成的货币贬值生活中价格总水平上升。货币量增长引起了通货膨胀。 10．短期中通货膨胀与失业如何相关? 答：短期中通货膨胀与失业之间存在着权衡取台，这是由于某些价格调整缓慢造成的。政府为了抑制通货膨胀会减少流通中的货币量，人们可用于支出的货币数量减少了，但是商品价格在短期内是粘性的，仍居高不下．于是社会消费的商品和劳务量减少，消费量减少又引起企业解雇工人。在短期内．对通货膨胀的抑制增加了失业量。 问题与应用
经济学原理名词解释 CHAPTER 1 Scarcity : the limited nature of society’s resources. Economics : the study of how society manages its scarce resources. Efficiency : the property of society getting the most it can from its scarce resources. Equity : the property of distributing economic prosperity fairly among the members of society. Opportunity cost : whatever must be given up to obtain some item. Marginal changes : small incremental adjustments to a plan of action. Market economy : an economy that allocates resources through the decentralized decisions of many firms and households as they interact in markets for goods and services. Market failure : a situation in which a market left on its own fails to allocate resources efficiently. Externality : the impact of one person’s actions on the well-being of a bystander. Market power : the ability of a single economic actor (or small group of actors) to have a substantial influence on market prices. Productivity : the quantity of goods and services produced from each hour of a worker’s time. Inflation : an increase in the overall level of prices in the economy. Phillips curve : a curve that shows the short-run tradeoff between inflation and unemployment. Business cycle : fluctuations in economic activity, such as employment and production. CHAPTER 2 Circular-flow diagram : a visual model of the economy that shows how dollars flow through markets among households and firms.
一、名词解释（每小题5分，共50分） 1.机会成本 2.科斯定理 3.搭便车 4.囚徒困境 5.菲利普斯曲线 6.供应学派 7.凯恩斯革命 8.看不见的手 9.比较优势 10.外部性 二、简述题（第11、12、13题各12分，14题14分，共50分） 1.简述银行存款的创造过程。 2.简述失业的根源及其类型。 3.简述节俭的是非。 4.根据有关经济学原理，简析我国森林减少、珍稀动物来绝的原因及解决的措施。 三、论述题(每小题25分，共计50分) 1.论述人民币升值对中国经济的影响。 2.论述政府公共投资对国民经济的作用。 一、名词解释（每小题5分，共50分） 1.机会成本:指人们利用一定资源获得某种收入时所放弃的在其他可能的用途中所能够获取的最大收入。生产一单位的某种商品的机会成本是指生产者所放弃的使用相同的生产要素在其他生产用途中所能得到的最高收入。机会成本的存在需要三个前提条件。第一，资源是稀缺的；第二，资源具有多种生产用途；第三，资源的投
向不受限制。从机会成本的角度来考察生产过程时，厂商需要将生产要素投向收益最大的项目，而避免带来生产的浪费，达到资源配置的最优。机会成本的概念是以资源的稀缺性为前提提出的。从经济资源的稀缺性这一前提出发，当一个社会或一个企业用一定的经济资源生产一定数量的一种或者几种产品时，这些经济资源就不能同时被使用在其他的生产用途方面。这就是说，这个社会或这个企业所能获得的一定数量的产品收入，是以放弃用同样的经济资源来生产其他产品时所能获得的收入作为代价的。这也是机会成本产生的缘由。因此，社会生产某种产品的真正成本就是它不能生产另一些产品的代价。所以，机会成本的含义是：任何生产资源或生产要素一般都有多种不同的使用途径或机会，也就是说可以用于多种产品的生产。但是当一定量的某种资源用于生产甲种产品时，就不能同时用于生产乙种产品。因此生产甲种产品的真正成本就是不生产乙种产品的代价，或者是等于该种资源投放于乙种产品生产上可能获得的最大报酬。一种资源决定用于甲种产品，就牺牲了生产其他产品的机会；从事生产甲种产品的收入，是由于不从事或放弃其他产品生产的机会而产生的。 2.科斯定理:指一种产权理论。科斯本人并未将科斯定理写成文字，科斯定理的提出是由其好友斯蒂格勒首先根据科斯于20世纪60年代发表的《社会成本问题》这篇论文的内容概括出来的。其内容是：只要财产权是明确的，并且其交易成本为0或者很小，则无论在开始时财产权的配置是怎么样的，市场均衡的最终结果都是有效率的。科斯定理进一步扩大了“看不见的手”的作用。按照这个定理，只要那些假设条件成立，则外部影响就不可能导致资源配置不当。或者以另一角度来说，在所给条件下，市场力量足够强大，总能够使外部影响以最经济的办法来解决，从而仍然可以实现帕累托最优状态。西方学者认为，明确的财产权及其转让可以使得私人成本（或利益）与社会成本（或利益）趋于一致。以污染问题为例，科斯定理意味着，一旦所需条件均被满足，则污染者的私人边际成本曲线就会趋于上升，直到与边际社会成本曲线完全重合，从而污染者的利润最大化产量将下降至社会最优产量水平。 科斯定理解决外部影响问题在实际中并不—定真的有效。资产的财产权不一定总是能够明确地加以规定；已经明确的财产权不一定总是能够转让；分派产权会影响收入分配，而收入分配的变动可以造成社会不公平，引起社会动乱。在社会动乱的情况下，就谈不上解决外部效果的问题了。 3.搭便车：指不付成本或支付很低的成本而消费公共产品的行为。公共产品的特点决定了私人厂商不愿自动提供这种产品。这是因为在公用产品消费中存在“搭便车”问题，即每个人都想不付任何成本，或只支付很低的代价，来享受公共产品的服务。由于公共物品具有消费的非竞争性和受益的非排他性，人们可以在不付费的情况下享受公共物品所带来的效益。因此公共产品覆盖的消费者人数越多，搭便车问题就越严重，公共产品由私人厂商提供出来的可能性就越小。例如：1970年美国通用汽车公司研制出了一种汽车污染物排放控制装置，每个售价20美金，如果每个车尾都装上这一装置，可使汽车排放的污染下降30％至50％。然而，污染的降低是一种公共产品，每个人呼吸空气质量是否改善并不取决于自己的车上是否装上这个新发明，而是取决于该地区大多数车主的选择，于是大多数人都不想多花20美元而只是试图搭便车，结果，在私人市场上，这种公共产品的产量总难以达到最佳水平。私人不能提供公共产品，就只能由政府出面担当此项职能。事实上，私人经济中的政府，最初就是为了提供公共产品(法律、国防、公安等等)的目的由众多私人共同建立起来的。政府这一职能具体体现为：①尽可能正确地估价社会对公用产品的实际需求；②按照社会福利最大化的原则确定税收比率，并用税收收入购置公用产品，为公众提供服务。 4.囚徒困境：指两个被捕获的囚犯之间的一种特殊“博弈”，说明为什么甚至在合作对双方有利时，保持合作也是困难的。囚犯两难处境的故事包含着一个一般性的结论，这个结论适用于任何一个力图维持其成员合作的集团。这是博弈论中的一个经典例证，同一市场上的寡头在力图达到垄断结果时的博弈类似于两个处于两难处境的囚犯的博弈。具体情况如下：两囚徒被指控是一桩罪案的同案犯。他们被分关在不同的牢房且无法互通信息。各囚徒都被要求坦白罪行。如果两囚徒都坦白，各将被判入狱5年；如果两人都不坦白，则很难对他们提起刑事诉讼，因而两囚徒可以期望被从轻发落为入狱2年；另一方面，如果一个囚徒坦白而另一个囚徒不坦白，坦白的囚徒就只需入狱1年，而另一个将被判入狱10年。那么囚徒将会怎么选择呢？下表归纳了各种可能的结果。（其中“得益”是负的，表格右下角单元格意思是两个囚徒各2年徒刑）。该表说明，这两个囚徒面临着一种困境。如果他们都不坦白（以一种会遵守的方法），那么两人只需入狱仅仅2年。但他们不能相互讲话，如果囚徒A不坦白，他就冒着被B利用的危险。因为不管囚徒A怎么选择，囚徒B坦白总是最优方案。
Examine why people tend to use common r esour ces too much Consider some of the impor tant common r esour ces in our economy Consider some of the impor tant public goods in our economy Lear n t he def ini ng characteristics of public goods and common r esour ces Examine why private markets fail to pr ovide public goods See why the cost-benefit analysis of public goods is both necessar y and dif ficult An old song lyric maintains that “the best things in life are free.” A moment’s thought reveals a long list of goods that the songwriter could have had in mind. Na-ture provides some of them, such as rivers, mountains, beaches, lakes, and oceans.The government provides others, such as playgrounds, parks, and parades. In each case, people do not pay a fee when they choose to enjoy the benefit of the good.Free goods provide a special challenge for economic analysis. Most goods in our economy are allocated in markets, where buyers pay for what they receive and sellers are paid for what they provide. For these goods, prices are the signals that guide the decisions of buyers and sellers. When goods are available free of charge,however, the market forces that normally allocate resources in our economy are absent. In this chapter we examine the problems that arise for goods without market prices. Our analysis will shed light on one of the Ten Principles of Economics P U B L I C G O O D S A N D C O M M O N R E S O U R C E S 225