NO.PZ2015120604000095
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. What is the percent of return that are less than $100,000 ?
选项:
A.0.05%.
B.0.13%.
C.2.28%.
解释:
C is correct.
z = (100000- 160000) /30000 = -2,
F(-2) = 1 - F(2)= 1 - 0.9772 = 0.0228
1:不懂为什么需要1减去F(-2)
2: 为什么我查的z table里的-2 = 0.02275