问题如下：
An analyst wants to test whether the means of two populations are equal. Which of the following statement is most appropriate?
选项：
A.Assumptions: normally distributed and independent populations, variance are equal.
How to test: F-test.
B.Assumptions: normally distributed and independent populations, variance are not equal.
How to test: F-test.
C.Assumptions: normally distributed populations, samples are not independent.
How to test: paired comparisions test.
解释：
C is correct.
If the two populations are normally distributed and independent, no matter the variance assumed equal or not, it will be most appropriate to use the T-test or Z-test.
请问使用paired test，normally distributed populations是必须有的前提条件吗？我看表格里没有这一条呀
