Question

What would happen if we conduct more than one t-test to compare the three methods?

1) We would fail to reject our null hypothesis.
2) We would increase our Type I error rate each time we do a t-test.
3) We would increase our Type II error rate each time we do a t-test.
4) We would fail to reject the null hypothesis for one of the comparisons.

Answer 1

Performing multiple t-tests increases the chance of making a Type I error, which is the incorrect rejection of a true null hypothesis.

When performing multiple t-tests to compare different sets of data, such as three different methods, we need to be wary of the error rates associated with hypothesis testing. Performing more t-tests increases the chance of making a Type I error, which is the incorrect rejection of a true null hypothesis. The correct choice from your options is, therefore, that we would increase our Type I error rate each time we conduct a t-test. In contrast, a Type II error is to fail to reject a false null hypothesis. The number of tests conducted does not directly increase the Type II error rate; however, other factors, such as sample size and effect size, can influence this rate.