* SAS commands for simple power calculations ;

data powcalc ;
 fcr1 = finv(.95,3,28) ;
 power1 = 1 - probf(fcr1,3,28,3.6) ;
 power2 = 1 - probf(fcr1,3,28,22.3) ;
 run ;
 proc print ; run ;

-----------------------------------------------------------------------

                  OBS      FCR1      POWER1     POWER2
                   1     2.94669    0.28630    0.97053

------------------------------------------------------------------------

 *SAS program to calculate sample sizes for CR designs ;

 * ngrp is the number of factor levels (p) in the CR-p design ;
 * rat is equal to:  (sum of alpha(i)^2)/sigma^2 ;

  %macro powcr(ngrp,rat,alpha,power) ;
    %local n ndf ddf nonc fcr pv ;
    data calc1 ;
    do n = 2 to 10000 ;
      ndf = &ngrp -1 ;  ddf = &ngrp*(n -1) ;
      nonc = &rat*n ;
      fcr = finv(1-&alpha,ndf,ddf) ;
      pv = 1 -probf(fcr,ndf,ddf,nonc) ;
      output ;
      if pv ge &power then leave ;
    end ;
    run ;
    proc print ; title 'Macro POWCR results' ;  run ;
    proc plot ; plot pv*n ; title 'Macro POWCR results' ; run ;
  %mend ;


  %powcr(4,.5,.05,.8) ;