NO.PZ2023061301000019
问题如下:
A pooled estimator is used when testing a hypothesis concerning the:
选项:
A.
equality of the variances of two normally distributed populations.
B.
difference between the means of two approximately normally distributed
populations with unknown but assumed equal variances.
C.
difference between the means of two at least approximately normally distributed
populations with unknown and assumed unequal variances.
解释:
B is correct. The assumption that the variances are equal allows for the combining
of both samples to obtain a pooled estimate of the common variance.
不太懂B和C的英文翻译