A t test is a statistical test that is used to compare the means of two groups. It is often used in hypothesis testing to determine whether a process or treatment actually has an effect on the population of interest, or whether two groups are different from one another. A t-test is used to compare the means (averages) of two groups and determine whether the differences between them are random or not random. It is any statistical hypothesis test in which the test statistic follows a Student’s t-distribution under the null hypothesis.

A t test can only be used when comparing the means of two groups (pairwise comparison). If you want to compare more than two groups, or if you want to do multiple pairwise comparisons, use an ANOVA test or a post-hoc test.

Use Case for t-test

You are studying iris flowers and you want to know whether the mean petal length of iris flowers differs according to their species.