NO.PZ2015121810000027
问题如下：
The prices of one-period, real default-free government bonds are likely to be most sensitive to changes in:
选项：
A.investors’ inflation expectations.
B.the expected volatility of economic growth.
C.the covariance between investors’ inter-temporal rates of substitution and the expected future prices of the bonds.
解释：
B is correct.
Only changes in default-free real interest rates will affect the price of real, default-free bonds. The average level of default-free real interest rates is positively related to the volatility of economic growth in the economy; thus, changes in the expected volatility of economic growth would likely lead to changes in real default-free real interest rates, which in turn would affect the prices of real, default-free government bonds.
考点：Discount Rate on Real Default-free Bonds
解析：排除法
A， real bonds不会受到通货膨胀的影响，nominal bonds才会。
B，volatility of economic growth影响分母l，即real default-free interest rate，所以B正确
C，one-period的债券价格不受covariance的影响，因为one-period default free bond的covariance=0。只有多期债券才会受covariance影响。
这里可不可以直接总结为：单期情况下，价格就是替代率，替代率只会受到经济好坏的影响，所以选未来经济的波动率
