1          OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;
 70         
 71         /*********************************  matpow1.sas ******************************/
 72         title 'Power analysis for fixed-effects factorial ANOVA: Matrix approach';
 73         proc iml;
 NOTE: IML Ready
 74         /********* Edit this input: Rows of matrices are separated by commas  ********/
 75              alpha = 0.05;
 76              wantpow = .80;
 77              f = {1,1,1,1,1,1};
 77       !                                  /* Relative sample sizes       */
 78              C = { 1 -1 -1  1  0  0,     /* Contrast matrix             */
 79                    0  0  1 -1 -1  1};
 80              eff = {0,-.5};
 80       !                                  /* In standard deviation units */
 81         /*****************************************************************************/
 82              p = nrow(f) ;
 82       !                    q = nrow(eff);
 82       !                                   f = f/sum(f);
 83         
 84         /*** Echoing input ***/
 85              print " Significance level: " alpha;
 86              print " Desired power: " wantpow;
 87              print " Relative sample sizes:" f;
 88              print " Contrast matrix ";
 88       !                                 print C;
 89              print " Effect matrix (in SD units): " eff;
 90         /*** Checking input ***/
 91              print " Checking input ...  ";
 92              inerr = 0;
 92       !                 /* Input error = no. This may be changed below */
 93              if nrow(C) ^= q then do;
 94                 print "Error: Length of eff must equal number of rows in C";
 95                 inerr=1;
 96              end;
 97              if ncol(C) ^= p then do;
 98                 print "Error: Length of f must equal number of cols in C";
 99                 inerr=1;
 100             end;
 101             if eff`*eff = 0 then do;
 102                print "Error: eff can't be zero; this would cause an infinite loop!";
 103                inerr=1;
 104             end;
 105             aa = min(f##2);
 106             if aa = 0 then do;
 107                print "Error: No sample size may be zero.";
 108                inerr=1;
 109             end;
 110        
 111        /*** Proceed if no input errors ***/
 112             if inerr = 1 then abort;
 113                else do;
 114                print "Input appears to be okay.  ";
 115                     core = inv(C*inv(diag(f))*C`);
 116                     effsize = eff`*core*eff;
 116      !                                        print " Effect size = " effsize;
 117                     power = 0;
 117      !                         n = p;
 117      !                                oneminus = 1-alpha;
 117      !                                                     /* Initializing ...*/
 118                     do until (power >= wantpow);
 119                        n = n+1 ;
 120                        ncp = n * effsize;
 121                        df2 = n-p;
 122                        power = 1-probf(finv(oneminus,q,df2),q,df2,ncp);
 123                     end;
 123      !                   /*  End Loop */
 124                     print " Required sample size is " n;
 125                end;
 125      !              /* End computation (Conditional on no input errors) */
 126        quit;
 NOTE: Exiting IML.
 NOTE: PROCEDURE IML used (Total process time):
       real time           0.05 seconds
       user cpu time       0.06 seconds
       system cpu time     0.00 seconds
       memory              2230.46k
       OS Memory           29604.00k
       Timestamp           03/18/2020 03:10:30 AM
       Step Count                        48  Switch Count  0
       Page Faults                       0
       Page Reclaims                     393
       Page Swaps                        0
       Voluntary Context Switches        0
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           8
       
 
 127        
 128        OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;
 139