Which condition must be met to conduct a test for the difference in two sample means using a z-statistic?
A) Data must be at least of nominal scale
B) Populations must be normal
C) Standard deviations of the two populations must be known
D) Samples are dependent

Question

Quizplus · Accepted Answer

To use a z-statistic for the difference in two sample means, the standard deviations of the two populations must be known.

Which Condition Must Be Met to Conduct a Test for the Difference