The z test for independent groups is seldom used because _________.
A) it lacks sensitivity
B) it is too complicated
C) we seldom know the population variances
D) the sampling distribution of z under H 0 is unknown

Question

Quizplus · Accepted Answer

The z test for independent groups requires knowledge of the population variances, which is often unknown. As a result, the t test for independent groups, which does not require knowledge of the population variances, is commonly used instead.

The Z Test for Independent Groups Is Seldom Used Because