Performing an analysis of variance (ANOVA)

Test if there is a difference between population means when a response variable is classified by one or more categorical variables (factors).

1. Select a cell in the dataset.
2. On the Analyse-it ribbon tab, in the Statistical Analyses group, click Fit Model, and then click ANOVA.
   The analysis task pane opens.
3. In the Y drop-down list, select the response variable.
4. In the Available variables list, select the factor variable(s):
   • To select a single variable, click the variable.
   • To select multiple variables, click the first variable then hold down the CTRL key and click each additional variable.
   • To select a range of variables, click the first variable then hold down the SHIFT key and click the last variable in the range.
5. Click Add Factor to add the simple factors.
6. To add the interaction between two or more factors, in the Terms list box, click the first term then hold down the CTRL key and click each additional term to include in the interaction, and then click Cross.
7. To remove a term, in the Terms list box, click the term and then click Remove.
   Note: It is sometimes quicker to use the Factorial command to build a factorial model and then remove any unnecessary terms.
8. To remove a factor and all terms using the factor, in the Factor list box, click the factor and then click Remove.

   When you select a factor, all terms that include the factor are selected. If you hold down the CTRL key and click additional factors, then all terms which include all the selected factors are selected.

9. Repeat steps 4 through 8 to build the model.
10. Click Calculate.