NO.PZ2019040801000010
问题如下：
In the incomplete probability matrix below, what is the joint probability of good economy and no interest rate increase?
选项：
A.
10%.
B.
20%
C.
30%
D.
40%
解释：
B is correct.
考点：Probability Matrix
解析：通过第一列利率提升的边际概率，得到C=10%。由此推得D=30%，B=50%。所以A=20%。
为什么边际概率是前两者之和
