When testing for the significance of the difference between two sample means,which of the following is almost always unknown?
A)the population standard deviations
B)the sample standard deviations
C)degrees of freedom
D)the sample means

Question

Quizplus · Accepted Answer

Population standard deviations are almost always unknown when testing for the significance of the difference between two sample means. Instead, we use the sample standard deviations to estimate the population standard deviations.

When Testing for the Significance of the Difference Between Two