题目
The mean equity risk premium over a 40-year period is equal to 8.0%. The standard deviation of the sample is 12%. The standard error of the sample mean is closest to:
选项
A.0.30%
B.1.90%
C.1.26%
D.8.00%
答案
B
解析
Note the size of the sample here is the number of years. Standard error of the mean is below 12%/√40=1.8974%标准误：12%/√40=1.8974%