When analyzing mean differences between three samples, doing all pairwise independent t tests instead of ANOVA using the same $\alpha$ level
A) decreases the probability of a Type I error.
B) increases the probability of a Type I error.
C) does not change the probability of a Type I error.
D) cannot be determined from the information provided.

Question

Quizplus · Accepted Answer

Conducting multiple pairwise independent t-tests instead of a single ANOVA increases the probability of a Type I error, which is the error of incorrectly rejecting the null hypothesis when it is true. This happens because each test carries its own risk of a Type I error, and the more tests you perform, the higher the overall risk of committing at least one Type I error across all the tests.

When Analyzing Mean Differences Between Three Samples, Doing All Pairwise α\alphaα

When Analyzing Mean Differences Between Three Samples, Doing All Pairwise $\alpha$