How to do an F-Test to Compare Two Variances

This article describes how to do an F-Test to compare two variances. An F-test of equality of variances is used to test for the null hypothesis that two normal populations have the same variance.

Requirements

A data set that contains a numeric outcome variable and a categorical variable with two groups you wish to compare.

Method

Select Anything > Advanced Analysis > Test > Variance > F-Test to Compare Two Variances
For Outcome, select the variable containing the numeric data
For Group, select the categorical variable containing the two groups you want to compare
OPTIONAL: Select Variable names to display variable names in the output instead of the variable labels
OPTIONAL: Select More decimal places to display more decimal places of precision in the output.