问题如下:
If the mean return on the S&P 500 is 9% per year, what is the mean return over one day, one week, and one month?
选项:
解释:
The mean scales linearly with the scale factor, and so 9%/ 252= .036%,
9%/ 52= 0.17%, and 9% /12= 0.75%.
不是應該除以根號252/根號52/根號12?