挤出（crowd out)

Y=C+I+G+NX

Y=5000

G=1000

T=1000

C=250+0.75(Y-T)

I=1000-50r

NX=500-500ε

r=r^*=5

a．在这个经济中，求出国民储蓄、投资、贸易余额以及均衡汇率。

b．现在G增加到1250，求出国民储蓄、投资、贸易余额以及均衡汇率的值。解释你的结果。

c．现在假设世界利率从5%上升到10%(G又是1000)，求出国民储蓄、投资、贸易余额以及均衡汇率的值。解释你的结果。

Consider an economy described by the following equations：

Y=C+I+G+NX

y=5000

G=1000

T=1000

C=250+0.75(Y-T)

I=1000-50r

NX=500-500ε

r=r^*=5

a．In this economy, solve for national saving, investment, the trade balance, and the equilibrium exchange rate.

b．Suppose now that G rises to 1,250. Solve for national saving, investment, the trade balance, and the equilibrium exchange rate. Explain what you find.

c．Now suppose that the world interest rate rises from 5 to 10 percent. (G is again 1,000). Solve for national saving, investment, the trade balance, and the equilibrium exchange rate. Explain what you find.

a．描述对财政紧缩(例如增加税收)做出反应会发生什么。把你的答案与小型开放经济的情况进行比较。

b．描述如果中央银行通过向公众购买债券来扩大货币供给，会发生什么变动。把你的答案与小型开放经济的情况进行比较。

Suppose that a large open economy has a fixed exchange rate.

a．Describe what happens in response to a fiscal contraction, such as a tax increase. Compare your answer to the ease of a small open economy.

b．Describe what happens if the central bank expands the money supply by buying bonds from the public. Compare your answer to the case of a small open economy.

Draft a letter to the senator described, explaining and evaluating the Ricardian view of government debt.

Do you believe the traditional or the Ricardian view of government debt？ Why？

How do the life-cycle and permanent-income hypotheses resolve the seemingly contradictory pieces of evidence regarding consumption behavior？