In order to make the test for the difference between two population means valid, the sample size in each independent sample must be the same.

Question

Quizplus · Accepted Answer

The test for the difference between two population means can still be valid even if the sample sizes are different. The assumption of equal sample sizes is not a strict requirement for such tests, although equal or similar sample sizes can increase the power of the test.

In Order to Make the Test for the Difference Between