Published by Alison Ramsey.
Last updated date: September 10, 2019.

The t-test is any statistical hypothesis test in which the test statistic follows a Student's t-distribution under the null hypothesis. The t-test can be used, for example, to determine if the means of two sets of data are significantly different from each other.

A t-test is most commonly applied when the test statistic would follow a normal distribution if the value of a scaling term in the test statistic were known. When the scaling term is unknown and is replaced by an estimate based on the data, the test statistics (under certain conditions) follow a Student's t distribution.