NO.PZ2015120604000060
问题如下:
According to the above table, what is the expected return of X?
选项:
A.1.
B.1.6.
C.-3.2.
解释:
A is correct
Expected return of X= (0.2)(-2) + (0.6)(1) + (0.2)(4) = 1
Joint Probability,是不是应该P(XY),那么不应该是X=-2,Y=5,同时发生的概率是0.2。为什么在计算的时候直接-2✖️0.2,0.2里面不会包含Y=5发生的概率吗。