Test for Equality of Variances in the Unpaired Samples Student's t test

Biostatistics BI 45, Saint Anselm College

F test for Equality of Variances - you must conduct this test and the variances must be equal in order to use the Unpaired Samples Student's t test.

Welch's Approximate t - this is used if the variances are unequal. Notice that observed t' also has a unique critical value for testing.