问题如下:
A fund manager finds that the return of funds in the market are normally distributed having a mean of $160,000 and a standard deviation of $30,000. The percent of stock investors that have incomes greater than $100,000?
选项:
A.34.13%.
B.68.26%.
C.97.72%.
解释:
C is correct.
Z=(100000 - 160000)/30000=F(-2).
1- F(-2) = F(2) = 0.9772.
你好,关于F(-2)=1-2=-1, 查表格的时候不应该是0.8413吗?如果我的思路不对,可以麻烦老师详细解释一下第二步吗?