Bartlett test

The Bartlett test is more effective than Levene test when we do not reject the hypothesis of normality of the data.

Example: We consider a data set with one factor and several levels, as in the following table.

 ^{click here to download the data}

To use the tool Tests of Variance the user must follow these steps: 

1. Access the menu:

Action ANOVA Tests of Variance

2. The following screen will be shown;

3. With the cursor in the field Factor, select the column that refers to the Factor (without the name of the column);

4. In Tests choose between the options Bartlett and Levene. In this case we will perform a Bartlett test;

5. With the cursor in the field Response Variable, select the column that refers to the Response Variable (without the name of the column);

6. In Show Results, choose one of the options. We suggest the option New Sheet, because Action does not have the undo command;

7. To finish, click Ok.

Results and Interpretation

Once the process is finishde, the following results will be shown:

We verity that the p-value of the test is bigger than the 5% significance level, so we accept the null hypothesis of equality of the variances.