曼昆经济学原理微观经济学英文版手工盒子
课后习题答案（考试章节筛选）
UNIT 1
SOLUTIONS TO TEXT PROBLEMS:
Quick Quizzes
1. The four principles of economic decisionmaking are: (1) people face tradeoffs; (2)
the cost of something is what you give up to get it; (3) rational people think at the
margin; and (4) people respond to incentives. People face tradeoffs becau to get
one thing that they like, they usually have to give up another thing that they like.
The cost of something is what you give up to get it, not just in terms of monetary
costs but all opportunity costs. Rational people think at the margin by taking an action
if and only if the marginal benefits exceed the marginal costs. People respond to
incentives becau as they compare benefits to costs, a change in incentives may
cau their behavior to change.
2. The three principles concerning economic interactions are: (1) trade can make
everyone better off; (2) markets are usually a good way to organize economic activity;
and (3) governments can sometimes improve market outcomes. Trade can make
everyone better off becau it allows countries to specialize in what they do best and
to enjoy a wider variety of goods and rvices. Markets are usually a good way to
organize economic activity becau the invisible hand leads markets to desirable
outcomes. Governments can sometimes improve market outcomes becau
sometimes markets fail to allocate resources efficiently becau of an externality or
market power.
3. The three principles that describe how the economy as a whole works are: (1) a
country’s standard of living depends on its ability to produce goods and rvices; (2)
prices ri when the government prints too much money; and (3) society faces a
short-run tradeoff between inflation and unemployment. A country’s standard of
living depends on its ability to produce goods and rvices, which in turn depends on
its productivity, which is a function of the education of workers and the access
workers have to the necessary tools and technology. Prices ri when the
government prints too much money becau more money in circulation reduces the
value of money, causing inflation. Society faces a short-run tradeoff between
inflation and unemployment that is only temporary and policymakers have some
ability to exploit this relationship using various policy instruments.
Questions for Review
1. Examples of tradeoffs include time tradeoffs (such as studying one subject over
another, or studying at all compared to engaging in social activities) and spending
tradeoffs (such as whether to u your last ten dollars on pizza or on a study guide for
that tough economics cour).
2. The opportunity cost of eing a movie includes the monetary cost of admission plus
the time cost of going to the theater and attending the show. The time cost depends
on what el you might do with that time; if it's staying home and watching TV, the
time cost may be small, but if it's working an extra three hours at your job, the time
cost is the money you could have earned.
3. The marginal benefit of a glass of water depends on your circumstances. If you've
just run a marathon, or you've been walking in the dert sun for three hours, the
marginal benefit is very high. But if you've been drinking a lot of liquids recently, the marginal benefit is quite low. The point is that even the necessities of life, like water, don't always have large marginal benefits.
4. Policymakers need to think about incentives so they can understand how people will
respond to the policies they put in place. The text's example of at belts shows that policy actions can have quite unintended conquences. If incentives matter a lot,
they may lead to a very different type of policy; for example, some economists have
suggested putting knives in steering columns so that people will drive much more
carefully! While this suggestion is silly, it highlights the importance of incentives.
5. Trade among countries isn't a game with some lors and some winners becau
trade can make everyone better off. By allowing specialization, trade between
people and trade between countries can improve everyone's welfare.
6. The "invisible hand" of the marketplace reprents the idea that even though
individuals and firms are all acting in their own lf-interest, prices and the
marketplace guide them to do what is good for society as a whole.
7. The two main caus of market failure are externalities and market power. An
externality is the impact of one person’s actions on the well-being of a bystander,
such as from pollution or the creation of knowledge. Market power refers to the
ability of a single person (or small group of people) to unduly influence market prices, such as in a town with only one well or only one cable television company. In
addition, a market economy also leads to an unequal distribution of income.
8. Productivity is important becau a country's standard of living depends on its ability
to produce goods and rvices. The greater a country's productivity (the amount of goods and rvices produced from each hour of a worker's time), the greater will be
its standard of living.
9. Inflation is an increa in the overall level of prices in the economy. Inflation is
caud by increas in the quantity of a nation's money.
10. Inflation and unemployment are negatively related in the short run. Reducing
inflation entails costs to society in the form of higher unemployment in the short run. Problems and Applications
1. a. A family deciding whether to buy a new car faces a tradeoff between the
cost of the car and other things they might want to buy. For example,
buying the car might mean they must give up going on vacation for the next
two years. So the real cost of the car is the family's opportunity cost in
terms of what they must give up.
b. For a member of Congress deciding whether to increa spending on
national parks, the tradeoff is between parks and other spending items or
tax cuts. If more money goes into the park system, that may mean less
spending on national defen or on the police force. Or, instead of
spending more money on the park system, taxes could be reduced.
c. When a company president decides whether to open a new factory, the
decision is bad on whether the new factory will increa the firm's profits
compared to other alternatives. For example, the company could upgrade
existing equipment or expand existing factories. The bottom line is: Which
method of expanding production will increa profit the most?
d. In deciding how much to prepare for class, a professor faces a tradeoff
between the value of improving the quality of the lecture compared to other
things she could do with her time, such as working on additional rearch.
2. When the benefits of something are psychological, such as going on a vacation, it isn't
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easy to compare benefits to costs to determine if it's worth doing. But there are two ways to think about the benefits. One is to compare the vacation with what you
would do in its place. If you didn't go on vacation, would you buy something like a
new t of golf clubs? Then you can decide if you'd rather have the new clubs or the vacation. A cond way is to think about how much work you had to do to earn the money to pay for the vacation; then you can decide if the psychological benefits of the vacation were worth the psychological cost of working.
3. If you are thinking of going skiing instead of working at your part-time job, the cost of
skiing includes its monetary and time costs, which includes the opportunity cost of the wages you are giving up by not working. If the choice is between skiing and going to the library to study, then the cost of skiing is its monetary and time costs including the cost to you of getting a lower grade in your cour.
4. If you spend $100 now instead of saving it for a year and earning 5 percent interest,
you are giving up the opportunity to spend $105 a year from now. The idea that
money has a time value is the basis for the field of finance, the subfield of economics that has to do with prices of financial instruments like stocks and bonds.
5. The fact that you've already sunk $5 million isn't relevant to your decision anymore,
since that money is gone. What matters now is the chance to earn profits at the
margin. If you spend another $1 million and can generate sales of $3 million, you'll earn $2 million in marginal profit, so you should do so. You are right to think that the project has lost a total of $3 million ($6 million in costs and only $3 million in revenue) and you shouldn't have started it. That's true, but if you don't spend the additional
$1 million, you won't have any sales and your loss will be $5 million. So what
matters is not the total profit, but the profit you can earn at the margin. In fact,
you'd pay up to $3 million to complete development; any more than that, and you
won't be increasing profit at the margin.
6. Harry suggests looking at whether productivity would ri or fall. Productivity is
certainly important, since the more productive workers are, the lower the cost per
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gallon of potion. Ron wants to look at average cost. But both Harry and Ron are
missing the other side of the equation−revenue. A firm wants to maximize its
profits, so it needs to examine both costs and revenues. Thus, Hermione is
right−it’s best to examine whether the extra revenue would excee d the extra costs.
Hermione is the only one who is thinking at the margin.
7. a. The provision of Social Security benefits lowers an individual’s incentive to
save for retirement. The benefits provide some level of income to the
individual when he or she retires. This means that the individual is not
entirely dependent on savings to support consumption through the years in
retirement.
b. Since a person gets fewer after-tax Social Security benefits the greater is his
or her earnings, there is an incentive not to work (or not work as much) after
age 65. The more you work, the lower your after-tax Social Security
benefits will be. Thus the taxation of Social Security benefits discourages
work effort after age 65.
8. a. When welfare recipients who are able to work have their benefits cut off
after two years, they have greater incentive to find jobs than if their benefits
were to last forever.
b. The loss of benefits means that someone who can't find a job will get no
income at all, so the distribution of income will become less equal. But the
economy will be more efficient, since welfare recipients have a greater
incentive to find jobs. Thus the change in the law is one that increas
efficiency but reduces equity.
9. By specializing in each task, you and your roommate can finish the chores more
quickly. If you divided each task equally, it would take you more time to cook than it would take your roommate, and it would take him more time to clean than it would
take you. By specializing, you reduce the total time spent on chores.
Similarly, countries can specialize and trade, making both better off. For example,
suppo it takes Spanish workers less time to make clothes than French workers, and French workers can make wine more efficiently than Spanish workers. Then Spain
and France can both benefit if Spanish workers produce all the clothes and French
workers produce all the wine, and they exchange some wine for some clothes. 10. a. Being a central planner is tough! To produce the right number of CDs by
the right artists and deliver them to the right people requires an enormous
amount of information. You need to know about production techniques
and costs in the CD industry. You need to know each person's musical
tastes and which artists they want to hear. If you make the wrong
decisions, you'll be producing too many CDs by artists that people don't want
to hear, and not enough by others.
b. Your decisions about how many CDs to produce carry over to other decisions.
You have to make the right number of CD players for people to u. If you
make too many CDs and not enough castte tapes, people with castte
players will be stuck with CDs they can't play. The probability of making
mistakes is very high. You will also be faced with tough choices about the
music industry compared to other parts of the economy. If you produce
more sports equipment, you'll have fewer resources for making CDs. So all
decisions about the economy influence your decisions about CD production.
11. a. Efficiency: The market failure comes from the monopoly by the cable TV
firm.
b. Equity
c. Efficiency: An externality aris becau condhand smoke harms
nonsmokers.
d. Efficiency: The market failure occurs becau of Standard Oil's monopoly
power.
e. Equity
f. Efficiency: There is an externality becau of accidents caud by drunk
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12. a. If everyone were guaranteed the best health care possible, much more of
our nation's output would be devoted to medical care than is now the ca.
Would that be efficient? If you think that currently doctors form a
monopoly and restrict health care to keep their incomes high, you might
think efficiency would increa by providing more health care. But more
likely, if the government mandated incread spending on health care, the
economy would be less efficient becau it would give people more health
care than they would choo to pay for. From the point of view of equity, if
poor people are less likely to have adequate health care, providing more
health care would reprent an improvement. Each person would have a
more even slice of the economic pie, though the pie would consist of more
health care and less of other goods.
b. When workers are laid off, equity considerations argue for the
unemployment benefits system to provide them with some income until they
can find new jobs. After all, no one plans to be laid off, so unemployment
benefits are a form of insurance. But there’s an efficiency problem why
work if you can get income for doing nothing? The ec onomy isn’t operating
efficiently if people remain unemployed for a long time, and unemployment
benefits encourage unemployment. Thus, there’s a tradeoff between
equity and efficiency. The more generous are unemployment benefits, the
less income is lost by an unemployed person, but the more that person is
encouraged to remain unemployed. So greater equity reduces efficiency.
13. Since average income in the United States has roughly doubled every 35 years, we
are likely to have a better standard of living than our parents, and a much better
standard of living than our grandparents. This is mainly the result of incread
productivity, so that an hour of work produces more goods and rvices than it ud to. Thus incomes have continuously rin over time, as has the standard of living.
14. If Americans save more and it leads to more spending on factories, there will be an
increa in production and productivity, since the same number of workers will have
more equipment to work with. The benefits from higher productivity will go to both the workers, who will get paid more since they're producing more, and the factory
owners, who will get a return on their investments. There is no such thing as a free lunch, however, becau when people save more, they are giving up spending.
They get higher incomes at the cost of buying fewer goods.
15. a. If people have more money, they are probably going to spend more on
goods and rvices.
b. If prices are sticky, and people spend more on goods and rvices, then
output may increa, as producers increa output to meet the higher
demand rather than raising prices.
c. If prices can adjust, then the higher spending of consumers will be matched
with incread prices and output won't ri.
16. To make an intelligent decision about whether to reduce inflation, a policymaker
would need to know what caus inflation and unemployment, as well as what苔的读音
determines the tradeoff between them. Any attempt to reduce inflation will likely
lead to higher unemployment in the short run. A policymaker thus faces a tradeoff
between the benefits of lower inflation compared to the cost of higher
unemployment.
UNIT2
SOLUTIONS TO TEXT PROBLEMS:
Quick Quizzes
1. Economics is like a science becau economists devi theories, collect data, and
analyze the data in an attempt to verify or refute their theories. In other words,
economics is bad on the scientific method.
Figure 1 shows the production possibilities frontier for a society that produces food
and clothing. Point A is an efficient point (on the frontier), point B is an inefficient
point (inside the frontier), and point C is an infeasible point (outside the frontier).
Figure 1
The effects of a drought are shown in Figure 2. The drought reduces the amount of food that can be produced, shifting the production possibilities frontier inward.
Figure 2
Microeconomics is the study of how houholds and firms make decisions and how
they interact in markets. Macroeconomics is the study of economy-wide phenomena, including inflation, unemployment, and economic growth.
2. An example of a positive statement is “higher taxes discourage work effort” (many
other answers are possible). That’s a positive statement becau it describes the
effects of higher taxes, describing the world as it is. An example of a normative
statement is “the government should reduce tax rates.” That is a normative
statement becau it’s a claim about how the world should be.
Parts of the government that regularly rely on advice from economists are the
Treasury Department in designing tax policy, the Department of Labor in analyzing
data on the employment situation, the Justice Department in enforcing the nation’s
antitrust laws, the Congressional Budget Office in evaluating policy proposals, and the
Federal Rerve in analyzing economic developments (many other answers are
possible).
3. Economic advirs to the president might disagree about a question of policy becau
of differing scientific judgments or differences in values.
Questions for Review
1. Economics is like a science becau economists u the scientific method. They
拨球devi theories, collect data, and then analyze the data in an attempt to verify or
refute their theories about how the world works. Economists u theory and
obrvation like other scientists, but they are limited in their ability to run controlled
experiments. Instead, they must rely on natural experiments.
2. Economists make assumptions to simplify problems without substantially affecting the
answer. Assumptions can make the world easier to understand.
3. An economic model cannot describe reality exactly becau it would be too
complicated to understand. A model is a simplification that allows the economist to
e what is truly important.
4. Figure 3 shows a production possibilities frontier between milk and cookies (PPF1). If
a dia kills half of the economy's cow population, less milk production is possible,
so the PPF shifts inward (PPF2). Note that if the economy produces all cookies, so it doesn't need any cows, then production is unaffected. But if the economy produces any milk at all, then there will be less production possible after the dia hits.
Figure 3
5. The idea of efficiency is that an outcome is efficient if the economy is getting all it can
from the scarce resources it has available. In terms of the production possibilities
frontier, an efficient point is a point on the frontier, such as point A in Figure 4. A
point inside the frontier, such as point B, is inefficient since more of one good could be produced with
out reducing the production of another good.
Figure 4
6. The two subfields in economics are microeconomics and macroeconomics.
Microeconomics is the study of how houholds and firms make decisions and how
they interact in specific markets. Macroeconomics is the study of economy-wide
phenomena.
7. Positive statements are descriptive and make a claim about how the world is, while
normative statements are prescriptive and make a claim about how the world ought
to be. Here is an example. Positive: A rapid growth rate of money is the cau of
inflation. Normative: The government should keep the growth rate of money low.
8. The Council of Economic Advirs is a group of economists who consult with the
president of the United States about economic matters. The Council consists of
three members and a staff of veral dozen economists. It writes the annual
Economic Report of the President.
9. Economists sometimes offer conflicting advice to policymakers for two reasons:
(1) economists may disagree about the validity of alternative positive theories about
how the world works; and (2) economists may have different values and, therefore,
different normative views about what public policy should try to accomplish. Problems and Applications
1. Many answers are possible.
2. a. Steel is a fairly uniform commodity, though some firms produce steel of
inferior quality.
b. Novels are each unique, so they are quite distinguishable.
c. Wheat produced by one farmer is completely indistinguishable from wheat
produced by another.
d. Fast food is more distinguishable than steel or wheat, but certainly not as
much as novels.
3. See Figure 5; the four transactions are shown.
Figure 5
4. a. Figure 6 shows a production possibilities frontier between guns and butter.
It is bowed out becau when most of the economy’s resources are being
ud to produce butter, the frontier is steep and when most of the
economy’s resources are being ud to produce gu ns, the frontier is very flat.
When the economy is producing a lot of guns, workers and machines best
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suited to making butter are being ud to make guns, so each unit of guns
given up yields a large increa in the production of butter. Thus, the
production possibilities frontier is flat. When the economy is producing a lot
of butter, workers and machines best suited to making guns are being ud
to make butter, so each unit of guns given up yields a small increa in the
production of butter. Thus, the production possibilities frontier is steep.
b. Point A is impossible for the economy to achieve; it is outside the production
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possibilities frontier. Point B is feasible but inefficient becau it’s inside the
production possibilities frontier.
Figure 6
c. The Hawks might choo a point like H, with many guns and not much butter.
The Doves might choo a point like D, with a lot of butter and few guns.
d. If both Hawks and Doves reduced their desired quantity of guns by the same
amount, the Hawks would get a bigger peace dividend becau the
production possibilities frontier is much steeper at point H than at point D.
As a result, the reduction of a given number of guns, starting at point H,
leads to a much larger increa in the quantity of butter produced than when
starting at point D.
5. See Figure 7. The shape and position of the frontier depend on how costly it is to
maintain a clean environment the productivity of the environmental industry.
Gains in environmental productivity, such as the development of a no-emission auto
engine, lead to shifts of the production-possibilities frontier, like the shift from PPF1 to PPF2 shown in the figure.
Figure 7
6. a. A family's decision about how much income to save is microeconomics.
b. The effect of government regulations on auto emissions is microeconomics.
