NO.PZ2015121810000033
问题如下：
One interpretation of an upward sloping yield curve is that the returns to short-dated bonds are:
选项：
A.uncorrelated with bad times.
B.more positively correlated with bad times than are returns to long-dated bonds.
C.more negatively correlated with bad times than are returns to long-dated bonds.
解释：
C is correct.
One interpretation of an upward sloping yield curve is that returns to short-dated bonds are more negatively correlated with bad times than are returns to long-dated bonds. This interpretation is based on the notion that investors are willing to pay a premium and accept a lower return for short-dated bonds if they believe that long-dated bonds are not a good hedge against economic "bad times".
考点：The Yield Curve on Nominal Default-free Bonds
对收益率曲线向上倾斜的一种解释是，与长期债券的回报相比，短期债券的回报与经济不景气的关系更为负相关。这种解释基于这样一种观念:如果投资者认为长期债券不能很好地对冲经济“不景气时期”的风险，他们就愿意为短期债券支付溢价并接受较低的回报。
老师，请问我的理解哪里有问题：
1、经济差的时候投资者会购买作为避险工具的国债，导致国债价格P上升，r下降。所以经济差，r下降，二者正相关。
2、短期债券比长期的更避险，买的人更多，r下降更厉害。所以短期债券r正相关更厉害。选B
