In testing the difference between two population means, for which the population variances are unknown and are not assumed to be equal, two independent samples of large sizes are drawn from the populations. Which of the following tests is appropriate?
A)z-test.
B)Pooled-variances t-test.
C)Unequal variances t-test.
D)Matched pairs t-test.

Question

Quizplus · Accepted Answer

The appropriate test in this scenario is the Unequal variances t-test, also known as Welch's t-test. This test does not assume equal variances and is more reliable when the population variances are not known. It is also appropriate for large sample sizes, which are given in the question. The z-test is only appropriate when the population variances are known or when the sample sizes are very large. The Pooled-variances t-test assumes equal variances and is not appropriate when the variances are unknown or unequal. The Matched pairs t-test is used when comparing two samples that are paired, such as before and after measurements.

In Testing the Difference Between Two Population Means, for Which