# If you are comparing subgroups of a data set, how can you determine if the variance between subgroups is significant?

Jul 22, 2016

hypothesis testing using ${\chi}^{2}$.

#### Explanation:

hypothesis testing using ${\chi}^{2}$.

The null hypothesis is ${\sigma}_{1}^{2} = {\sigma}_{2}^{2}$
The alternate is ${\sigma}_{1}^{2} \ne {\sigma}_{2}^{2}$

The test statistic is $t = {\sigma}_{1}^{2} / {\sigma}_{2}^{2}$. The more we deviate from 1 the more likely we are to reject the null.