To compare means
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1    Choose Stat > ANOVA > General Linear Model > Comparisons.

2    In Response, choose the response variable.

3    In Type of comparisons, choose the type of comparisons to perform.

·    Choose Pairwise when you want to compare all combinations of means for the selected terms.

·    Choose With a control to compare treatment means to the mean of a control group. When this method is suitable, it is inefficient to use pairwise comparisons because the confidence intervals are wider and the hypothesis tests are less powerful for a given family error rate.

4    In Method, check the multiple comparison method that you want to use. Read Multiple comparisons of means to learn how to choose among the options.

5    In Terms for comparisons, select the terms that you want to compare and click C = Compare levels for this item. Or, double-click the terms that you want to compare.

6    In Control Levels, if you chose With a control, you must choose a control level for each factor that you select.

7    If you like, use any dialog box options, then click OK.