问题如下:
Which of the following statements on a pooled estimator most appropriate?
选项:
A.It's an equality of the variances of two normally distributed populations.
B.It's an estimate drawn from the combination of two different samples.
C.It's only be used in t-test.
解释:
B is correct. A pooled estimate is an estimate drawn from the combination of two different samples. It's used when testing the concerning difference between means.
请问A怎么翻译呀?C错在哪了,不就只在t分布时候提及吗?