How Do You Know If Variances Are Equal

If the variances are equal, the ratio of the variances will equal 1. For example, if you had two data sets with a sample 1 (variance of 10) and a sample 2 (variance of 10), the ratio would be 10/10 = 1. You always test that the population variances are equal when running an F Test.

What does it mean for variances to be equal?

Equal variances (homoscedasticity) is when the variances are approximately the same across the samples. … If you are comparing two or more sample means, as in the 2-Sample t-test and ANOVA, a significantly different variance could overshadow the differences between means and lead to incorrect conclusions.

What does UNequal variances mean?

The conservative choice is to use the “Unequal Variances” column, meaning that the data sets are not pooled. This doesn’t require you to make assumptions that you can’t really be sure of, and it almost never makes much of a change in your results.