/* We specify the arrangement of treatment population means for which we want to calculate the power */


DATA Exemplary;
      do Gender = 1 to 2;
         do Age = 1 to 3;
            input LearnTm @@;
            output;
         end;
      end;
      datalines;
         10 14 18
         7 10 13
      ;
   run;

/* We also conjecture that the error standard deviation is about 3 minutes. */

PROC GLMPOWER data=Exemplary;
CLASS Gender Age;
MODEL LearnTm = Gender Age Gender*Age;
POWER
   stddev = 3
   ntotal = 30
   power  = .;
RUN;

/* We can specify a range of guesses for sigma. */

PROC GLMPOWER data=Exemplary;
CLASS Gender Age;
MODEL LearnTm = Gender Age Gender*Age;
POWER
   stddev = 2 4
   ntotal = 30
   power  = .;
RUN;



/* We can plot the power for a variety of total sample sizes. */

PROC GLMPOWER data=Exemplary;
CLASS Gender Age;
MODEL LearnTm = Gender Age Gender*Age;
POWER
   stddev = 3
   ntotal = 30
   power  = .;
PLOT x=n min=18 max=90;
RUN;