When calculating the standard error of ,under what assumption do you pool the sample variances and ?
A) Known population variances.
B) Unknown population variances that are assumed equal.
C) Unknown population variances that are assumed unequal.
D) All of these choices are correct.

Question

When calculating the standard error of  ,under what assumption do you pool the sample variances  and  ?
A) Known population variances. 
B) Unknown population variances that are assumed equal. 
C) Unknown population variances that are assumed unequal. 
D) All of these choices are correct.

Quizplus · Accepted Answer

When calculating the standard error of the mean, we assume that the population variances are unknown but equal. Therefore, we pool the sample variances in order to estimate the common variance of the population. This assumption allows us to use the pooled estimate of variance in the calculation of the standard error of the mean.

When Calculating the Standard Error of ,Under What Assumption