NO.PZ2020010304000050
问题如下:
If you are given a 99% confidence interval for the mean return on the Nasdaq 100 of [2.32%, 12.78%], what is the sample mean and standard error? If this confidence interval is based on 37 years of data, assumed to be iid, what is the sample standard deviation?
解释:
The mean is the midpoint of a symmetric confidence interval (the usual type), and so is 7.55%.
The 99% CI is constructed as and so = 12.78% - 7.55% = 5.23%. The critical value for a 99% CI corresponds to the point where there is 0.5% in each tail, or 2.57, and so =5.23% /2.57=2.03% needs to be surveyed.
If this confidence interval is based on 37 years of data, assumed to be iid, the sample standard deviation is
此题已经给定均值方差,解题思路不明。