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Using SAS Choose Design ANOVA Compare Means Regression Examples
Comparing Means      


To change mean separation method (test):                                 See a comparison of methods here
The default mean separation test is Fisher's Least Significant Difference. Other mean separation methods supported by Proc MIXED can be requested, using the ADJUST= option. 

An example is %MMAOV(one,yvar,CLASS=treat, FIXED=treat, ADJUST=tukey);
Using the ADJUST= option, you can choose one of these methods:

To change the significance level:
Use the ALPHA= option to change from the default 5% significance level, for example:
      %MMAOV(one,yvar,CLASS=treat, FIXED=treat, ADJUST=tukey, ALPHA=.01);

To sort the means:

By default, means are sorted by level name, with treatment A listed before treatment B.  But if there are many treatments, sorting by mean value can make interpretation of the mean separation letters easier.  Do this with the SORT= option, for example:
     %MMAOV(one,yvar,CLASS=treat, FIXED=treat, ADJUST=tukey, SORT=yes);

To see individual comparison probabilities:

The conventional letter grouping only shows if means differ at a chosen significance level.  You may want to know the P-value for comparing two means.  Request this additional output using the MIXDIFFS option,
     %MMAOV(one,yvar,CLASS=treat, FIXED=treat, MIXDIFFS=yes);
Beware that extensive output can be produced, since a line is printed for every pair of means.

To test if means are equal to 0:

Proc MIXED automatically tests if each mean is equal to zero, but this is generally of no practical use, so %MMAOV does not print the tests (default TEST0=no).  If you would like to see these results, use TEST0=yes. For example:
     %MMAOV(one,yvar,CLASS=treat, FIXED=treat, MIXDIFFS=yes, TEST0=yes);

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