DATA Fat;
INPUT Fat Absorb;
CARDS;
1 70
2 73.333
3 76.667
4 80
RUN;


*ODS Listing Close;  *Turn off Listing; 
Proc Mixed noprofile;
    Classes Fat;
    Model Absorb=Fat;
    Parms (100) /NoIter;
    Contrast '1 VS 2' Fat 1 -1 0 0;
*    ODS Output Tests3=anova;
*    ODS Output Contrasts=contr;
make 'tests' out=anova;
make 'contrast' out=contr;

Data Power;
    Set anova contr;
    t=4;
*    if Effect ne ' ' then Source=Effect;
*    if Label ne ' ' then Source=Label;
fvalue=f;
numdf=ndf;
dendf=ddf;
    ALPHA = 0.05;                       * The desired Type I error rate ;
    do n=6 to 25 by 1;
        DenDF=t*(n-1);
        FCRIT = FINV(1- ALPHA,NumDF, DenDF, 0);  
          * The 0 represents non-centrality parameter ;
        NONCENT = N*NumDF*Fvalue;                 * The non-centrality parameter ;
        POWER = 1 - PROBF(FCRIT, NumDF, DenDF, NONCENT);
        output;
        end;
run;

*ODS Listing;
PROC PRINT;
    var Source n numdf dendf NonCent Power;
RUN;