-国际经济学克鲁格曼-教材答案.doc

Problems and Answers to Chapter 2
Q1: Canada and Australia are (mainly) English-speaking countries with populations that are not too different in size (Canada’s is 60 percent larger). But Canadian trade is twice as large, relative to GDP, as Australia’s. Why should this be the case?
加拿大和澳大利亚都是英语国家，两国的人口规模也相当（加拿大多60%），但是相对各自的GDP而言，加拿大的贸易额是澳大利亚的两倍，为什么如此？
A1:According to Gravity Model, GDP is not the only factor to explain the volume of
trade between two countries, because distance is also an important factor. Considering
the distance, the transportation cost of Australia is relatively higher than that of
Canada, so the attractiveness of trade is reduced. However, Canada is close to the
USA which is a large economy while Australia is not close to any large economy,
making Canada more open while Australia is more autarky.
GDP 不是解释两国贸易量的唯一重要因素，距离也是至关重要的因素之一。
考虑到距离，澳大利亚的进出口运输成本相对更高，因此减少了贸易吸引力。
因为加拿大与美国相邻，而澳大利亚不与任何一个大经济体相邻，这使得加拿
大更加开放，而澳大利亚更加自给自足。

Q2:Mexico and Brazil have very different trading patterns. Mexico trades mainly
with the United States, Brazil trades about equally with the United States and with the
European Union; Mexico does much more trade relative to its GDP. Explain these
differences using the gravity model.
墨西哥和巴西各自的贸易模式不同。墨西哥主要与美国贸易，巴西与美国和
欧盟的贸易量大致相当。墨西哥的贸易量相对其GDP而言很大。用引力模型
解释这种现象。
A2:Mexico is close to the United States, but is very far from the European Union, so
Mexico’s value of trade with the United States is large. Brazil is far from both the
United States and European Union, thus, Brazil’s volume of trade with the United
States and with the European Union is generally equivalent. Mexico’s volume of trade
is larger than Brazil’s, for two reasons: one is that Mexico is adjacent to the United
States which is a large economy; the other is that Mexico is one of the members of
NAFTA. Brazil is far from any large economy, and the size of the economy for the
countries which have signed free trade agreements with Brazil is relatively small.

墨西哥与美国毗邻，但是距离欧盟很远，因此它与美国的贸易量很大。巴西
离美国和欧盟都很远，因此巴西与美国和欧盟的贸易量大致相当。墨西哥贸易
量比巴西大，其原因一方面由于墨西哥离大经济体美国近，另一方面由于它是
北美贸易协定的成员国之一。巴西远离任何一个大经济体，与它签订自由贸易
协定的国家经济规模都比较小。

Q3:Equation (2.1) says that trade between any two countries is proportional to the
product of their GDPs. Does this mean that the GDP of every country in the world
were to increase by 50%, world trade would increase by 125%? Analyze the question
using the simple example shown in Table 2-2.
方程(2.1) 表明两个国家之间的贸易和它们的GDP乘积成正比。这是否意味着如果
每个国家的GDP增加50%, 世界的贸易量就增加125%？分析这个问题用表格2-2
的简单例子。
A3:Yes. If both countries’GDP increase by 50%, other things equal, multiplying the
right hand side of equation (2.1) by (1+50%)*(1+50%)=225% and multiplying the left
hand side of equation (2.1) by 1+125%=225%, therefore, the volume of trade will increase 125%. Using Table 2-2, if four countries’GDP all increase 50%, the volume of trade will increase 125% correspondingly, so the first line of the table will become: —1.6*225%=3.6 0.4*225% =0.9 0.4*225% =0.9 Country A’s GDP increases to 4*(1+50%) =6 > (3.6+0.9+0.9= 5.4). According to the assumption, the results are reasonable because the results mean that part of country A’s income is consumed on imports and part of country A’s income is
consumed on domestic products, although the portion consumed domestically is smaller than that of imports.
是的。如果两个国家的GDP均增加50%，其他条件不变，方程(2.1) 的右边乘以(1+50%)*(1+50%)=225%, 方程式的左边乘以1+125%=225%，所以，世界的贸易量就增加125%。结合表格2-2，如果四个国家的GDP都增加50%倍，贸易量也增加125%，则表格第一行的数据应为：—1.6*225%=3.6 0.4*225% =0.9 0.4*225% =0.9 A国的GDP增加到4*(1+50%)=6 > (3.6+0.9+0.9= 5.4)。根据假设，这个结果是合理的因为这意味着A国的支出一部分从国外进口一部分收入用于消费本国的产品，虽然用于本国消费的部分少于对其他国家的进口。

Q4: Over the past few decades, East Asian economies have increased their share of
world GDP. Similarly, intra-East Asian trade --- that is, trade among East Asian
nations --- has grown as a share of world trade. More than that, East Asian countries
3 do an increasing share of their trade with each other. Explain why, using the gravity
model.

在过去的几十年中，东亚国家增加了它们在世界GDP中的份额。同样，不
仅东亚国家整体的贸易在世界贸易中的份额增加了，而且东亚国家内相互间的
贸易也增加了。应用引力模型解释这一现象。
A4:

In the past, East Asian countries are all small economies, meaning that their size
of economies is small and they are unable to import a lot of goods. As these East
Asian countries become richer, the demand increases and they can import more than
before. Considering that East Asian countries have been rich countries, they become
trading partners with each other; however, they mainly imported goods from rich
countries. Based on gravity model, even if the distance between South Korea and
Taiwan is small, the volume of the two countries is very small due to their small size
of economies. But now, because their GDP have increased, the volume of trade
between the two countries increased correspondingly.
之前，东亚国家都是小经济体，这说明它们的市场规模很小，不能大量进口。随着它们越来越富裕，消费需求增加，它们也就能更多地进口了。这样，之前它们主要向富国出口，现在它们自己成为了富国，互相也就成为了贸易对象。根据引力模型，当韩国和台湾GDP
规模很小时，意味着尽管两国的距离很近，但是两国之间的贸易量很小。现在它们GDP增加了，它们之间的贸易量也随之增大了。

Q5:A century ago, most French imports came from relatively distant locations: North
America, Latin America, and Asia. Today, most French imports come from other
European countries. How does this fit with the changing types of goods that make up
world trade?
一个世纪以前，法国的进口产品来自相对遥远的地区：北美、拉丁美洲，和
亚洲。今天，法国绝大部分进口产品来自其他欧洲国家。这种变化是如何迎合
不断变化的世界贸易产品结构的？
A5:A century ago, each country’s trading products are determined by the country’
s climate and geography. The climate and natural resources endowments in French are
very similar to that of other European countries; therefore, French can only import
different products, such as, cotton, rubber, and etc, from other western hemisphere

(North America, Latin America) and Asia. However, after industrial revolution,
manufacturing trade increased dramatically. With the development of transportation
and communicate technology, French’s trade volume with other European countries
increases correspondingly, as the gravity model predicted directly.
一个世纪以前，各国贸易产品是由气候和地理条件决定的。法国的气候和自
然资源禀赋和欧洲其他国家很相似，这样法国只能从西半球其他国家、亚洲进
口像棉花、橡胶这样的产品，从欧洲其他国家进口产品很少。工业革命之后，
制造品贸易增长，并且随着交通和通讯的改进继续扩张，因此法国转向与欧洲
其他经济体大量开展贸易是自然而然的，这就是引力模型的一个直接预测。

Chapter 3
1．Home has 1200 units of labor available. It can produce two goods, apples and bananas. The unit labor requirement in apple production is 3, while in banana production it is 2.
a．Graph out the production possibilities frontier:

b．What is the opportunity cost of apples in terms of bananas?

c．In the absence of trade, what would the price of apples in terms of bananas be?
In the absence of trade, since labor is the only factor of production and supply decisions are determined by the attempts of individuals to maximize their earnings in a competitive economy, only when will both goods be produced. So
在没有贸易时，因为劳方是唯一的生产要素，并且供应决定取决于个体尝试最大化他们的在竞争经济的收入，只有当两件物品将被生产。 因此
2．Home is as described in problem 1. There is now also another country, Foreign, with a labor force of 800. Foreign’s unit labor requirement in apple production is 5, while in banana production it is 1.

a．Graph Foreign’s production possibilities frontier:

b．Construct the world relative supply curve.

3．Now suppose world relative demand takes the following form: Demand for apples/demand for bananas = price of bananas/price of apples.
a．Graph the relative demand curve along with the relative supply curve:

∵When the market achieves its equilibrium, we have
∴RD is a hyperbola

b．What is the equilibrium relative price of apples?
The equilibrium relative price of apples is determined by the intersection of the RD and RS curves.
RD:
RS:
∴
∴
c．Describe the pattern of trade.
∵
∴In this two-country world, Home will specialize in the apple production, export apples and import bananas. Foreign will specialize in the banana production, export bananas and import apples.
d．Show that both Home and Foreign gain from trade.

International trade allows Home and Foreign to consume anywhere within the colored lines, which lie outside the countries’ production possibility frontiers. And the indirect method, specializing in producing only one production then trade with other country, is a more efficient method than direct production. In the absence of trade, Home could gain three bananas by foregoing two apples, and Foreign could gain by one foregoing five bananas. Trade allows each country to trade two bananas for one apple. Home could then gain four bananas by foregoing two apples while Foreign could gain one apple by foregoing only two bananas. So both Home and Foreign gain from trade.
国际贸易允许本国和外国任何地方在分界线之内消耗，在一国生产可能性边境之外说谎。 并且间接方法，专门研究导致一生产比直接生产然后只换与其他国家，是一个高效率的方法。 在没有贸易时，首页可能由前面二个苹果获取三个香蕉，并且外国可能由一前面五个香蕉获取。 贸易允许每个国家为一个苹果换二个香蕉。 首页只能由前面二个苹果然后获取四个香蕉，当外国时能由前面二个香蕉获取一个苹果。 因此首页和从贸易的外国获取。
4．Suppose that instead of 1200 workers, Home had 2400. Find the equilibrium relative price. What can you say about the efficiency of world production and the division of the gains from trade between Home and Foreign in this case?
RD:
RS
∴
∴

In this case, Foreign will specialize in the banana production, export bananas and import apples. But Home will produce bananas and apples at the same time. And the opportunity

cost of bananas in terms of apples for Home remains the same. So Home neither gains nor loses but Foreign gains from trade.
在这种情况下，外国将专门研究香蕉生产，出口香蕉和进口苹果。 但是本国同时将生产香蕉和苹果。 并且香蕉的机会成本根据苹果的本国的依然是同样。 因此本国不获取也不丢失，而是从贸易的外国获取。
5．Suppose that Home has 2400 workers, but they are only half as production in both industries as we have been assuming, Construct the world relative supply curve and determine the equilibrium relative price. How do the gains from trade compare with those in the case described in problem 4?
In this case, the labor is doubled while the productivity of labor is halved, so the ＂effective labor＂remains the same. So the answer is similar to that in 3. And both Home and Foreign can gain from trade. But Foreign gains lesser compare with that in the case 4.
6．”Korean workers earn only $2.50 an hour; if we allow Korea to export as much as it likes to the United States, our workers will be forced down to the same level. You can’t import a $5 shirt without importing the 2.50 wage that goes with it.” Discuss.
In fact, relative wage rate is determined by comparative productivity and the relative demand for goods. Korea’s low wage reflects the fact that Korea is less productive than the United States in most industries. Actually, trade with a less productive, low wage country can raise the welfare and standard of living of countries with high productivity, such as United States. So this pauper labor argument is wrong.
实际上，相对工资率取决于比较生产力和对物品的相对需求。 Korea’s低工资反射事实韩国比多数产业的美国较不有生产力的。 实际上，与一个较不有生产力，低工资国家的贸易可能培养国家福利和生活水平有高生产力的，例如美国。 因此这个叫花子劳方论据是错误的。

7．Japanese labor productivity is roughly the same as that of the United States in the manufacturing sector (higher in some industries, lower in others), while the United States, is still considerably more productive in the service sector. But most services are non-traded. Some analysts have argued that this poses a problem for the United States, because our comparative advantage lies in

things we cannot sell on world markets. What is wrong with this argument?
The competitive advantage of any industry depends on both the relative productivities of the industries and the relative wages across industries. So there are four aspects should be taken into account before we reach conclusion: both the industries and service sectors of Japan and U.S., not just the two service sectors. So this statement does not bade on the reasonable logic.
所有产业的竞争优势取决于产业的相对生产力和横跨产业的亲戚薪水。 因此，在我们得出结论之前，有四个方面应该考虑到 产业和日本和美国，不仅二个服务部门的服务部门。 不因此这个声明在合理的逻辑出了价。
8．Anyone who has visited Japan knows it is an incredibly expensive place; although Japanese workers earn about the same as their U.S. counterparts, the purchasing power of their incomes is about one-third less. Extend your discussing from question 7 to explain this observation. (Hint: Think about wages and the implied prices of non-trade goods.)
The relative higher purchasing power of U.S. is sustained and maintained by its considerably higher productivity in services. Because most of those services are non-traded, Japanese could not benefit from those lower service costs. And U.S. does not have to face a lower international price of services. So the purchasing power of Japanese is just one-third of their U.S. counterparts.
美国的相对更高的购买力由它的在服务的相当地更高的生产力承受并且维护。 由于大多那些服务non-traded，日语不可能受益于那些更低的服务费用。 并且美国不必须面对服务的一个更低的国际价格。 因此日语的购买力是他们的美国相对物的三分之一。
9．How does the fact that many goods are non-traded affect the extent of possible gains from trade?
Actually the gains from trade depended on the proportion of non-traded goods. The gains will increase as the proportion of non-traded goods decrease.
10．We have focused on the case of trade involving only two countries. Suppose that there are many countries capable of producing two goods, and that each country has only one factor of production, labor. What could we say about the pattern of production and in this case? (Hint: Try constructing the world relative supply curve.)

Any countries to the left of the intersection of the relative demand and relative supply curves export the good in which they have a comparative advantage relative to any country to the right of the intersection. If the intersection occurs in a horizontal portion then the country with that price ratio produces both goods.
Chapter 4
1. In 1986, the price of oil on world markets dropped sharply. Since the United States is an oil-importing country, this was widely regarded as good for the U.S. economy. Yet in Texas and Louisiana 1986 was a year of economic decline. Why?
It can deduce that Texas and Louisiana are oil-producing states of United States. So when the price of oil on world markets declined, the real wage of this industry fell in terms of other goods. This might be the reason of economic decline in these two states in 1986.
2。An economy can produce good 1 using labor and capital and good 2 using labor and land. The total supply of labor is 100 units. Given the supply of capital, the outputs of the two goods depends on labor input as follows:

To analyze the economy’s production possibility frontier, consider how the output mix changes as labor is shifted between the two sectors.
a. Graph the production functions for good 1 and good 2.

b. Graph the production possibility frontier. Why is it curved?
Q1
Q2
L1
L2
PPF

The PPF is curved due to declining marginal product of labor in each good. The total labor supp