Cookbook for Checking the **Equal Variance Assumption**

**Minitab** uses a homogeneity of variance test for assessing equal variances.

To check equal variances for two or more samples of data

1. Go to the Stat menu, select **ANOVA**.

2. Select Test for Equal Variances

3. In the Response box, enter the column containing the Y data.

4. In the Factors box, enter the factor or factors. For a two-sample t-test, the factor is simply an indicator variable which states which sample the each Y value belongs in. For **ANOVA**, there are 2 or more factors.

5. Click Okay.

6. You will see a display as shown below. Check the p-value associated with the Bartlett’s test, Levene’s test, or F test. Also check the confidence intervals for the standard deviations.

Please don’t hesitate to comment should you have any additional questions regarding the Equal Variance Assumption

## Use of Equal Variance Assumption with ANOVA

*Used with permission from sixsigmaz.com*

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