1          OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;
 70         
 71         /******************************  matpow2.sas ******************************/
 72         title 'Power analysis for fixed-effects factorial ANOVA: Matrix approach';
 73         title2 'Specify a beta vector instead of just an effect';
 74         proc iml;
 NOTE: IML Ready
 75         /********* Edit this input: Rows of matrices are separated by commas  ********/
 76              alpha = 0.05;
 77              wantpow = .80;
 78              f = {1,1,1,1,1,1};
 78       !                                  /* Relative sample sizes       */
 79              C = { 1 -1 -1  1  0  0,     /* Contrast matrix             */
 80                    0  0  1 -1 -1  1};
 81              beta = {0,.25,0,.25,0,-.25};
 82         
 83                       /* In standard deviation units */
 84         /*****************************************************************************/
 85              eff = C*beta;
 86              r = nrow(f) ;
 86       !                    q = nrow(eff);
 86       !                                   f = f/sum(f);
 87         /*** Echoing input ***/
 88              print " Significance level: " alpha;
 89              print " Desired power: " wantpow;
 90              print " Relative sample sizes:" f;
 91              print " Contrast matrix ";
 91       !                                 print C;
 92              print " Beta matrix (in SD units): " beta;
 93              print " Effect (h) matrix in SD units: " eff;
 94         /*** Checking input ***/
 95              print " Checking input ...  ";
 96              inerr = 0;
 96       !                 /* Input error = no. This may be changed below */
 97              if nrow(C) ^= q then do;
 98                 print "Error: Length of eff must equal number of rows in C";
 99                 inerr=1;
 100             end;
 101             if ncol(C) ^= r then do;
 102                print "Error: Length of f must equal number of cols in C";
 103                inerr=1;
 104             end;
 105             if eff`*eff = 0 then do;
 106                print "Error: eff can't be zero; this would cause an infinite loop!";
 107                inerr=1;
 108             end;
 109             aa = min(f##2);
 110             if aa = 0 then do;
 111                print "Error: No sample size may be zero.";
 112                inerr=1;
 113             end;
 114        
 115        /*** Proceed if no input errors ***/
 116             if inerr = 1 then abort;
 117                else do;
 118                print "Input appears to be okay.  ";
 119                     core = inv(C*inv(diag(f))*C`);
 120                     effsize = eff`*core*eff;
 120      !                                        print " Effect size = " effsize;
 121                     power = 0;
 121      !                         n = r+1;
 121      !                                  oneminus = 1-alpha;
 121      !                                                       /* Initializing ...*/
 122                     do until (power >= wantpow);
 123                        n = n+1 ;
 124                        ncp = n * effsize;
 125                        df2 = n-r;
 126                        power = 1-probf(finv(oneminus,q,df2),q,df2,ncp);
 127                     end;
 127      !                   /*  End Loop */
 128                     print " Required sample size is " n;
 129                end;
 129      !              /* End computation (Conditional on no input errors) */
 130        quit;
 NOTE: Exiting IML.
 NOTE: PROCEDURE IML used (Total process time):
       real time           0.06 seconds
       user cpu time       0.06 seconds
       system cpu time     0.00 seconds
       memory              2331.81k
       OS Memory           29604.00k
       Timestamp           03/18/2020 03:07:57 AM
       Step Count                        42  Switch Count  0
       Page Faults                       0
       Page Reclaims                     373
       Page Swaps                        0
       Voluntary Context Switches        0
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           0
       
 
 131        
 132        OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;
 143