/* fitness2.sas */
options ls=72 ps=60;
data fitness;
   infile 'fitness.dat';
   input y x1 x2 x3 x4 x5 x6;
/* y = oxygen
   x1 = age
   x2 = weight
   x3 = runtime
   x4 = restpulse
   x5 = runpulse
   x6 = maxpulse  */
proc reg data=fitness;
   model y = x1-x6 / selection=forward slentry=.10 details;
   model y = x1-x6 / selection=backward slstay=.10 details;
   model y = x1-x6 / selection=stepwise slentry=.10 slstay=.10 details;
title 'sequential selection methods';
proc reg data=fitness;
   model y = x3 / ss1 ss2;
      output out=model03 p=yhat r=resid;
title 'model with x0 and x3';
proc plot data=model03;
   plot resid*yhat / vref=0;
   plot resid*x3 / vref=0;
proc print data=model03;
   var y x3 yhat resid;
proc univariate data=model03 plot normal;
     var resid;
proc rank data=model03 normal=blom out=new1;
     var resid;
     ranks normsc;
proc print data=new1;
   var resid normsc;
proc plot data=new1;
     plot resid*normsc;
proc reg data=fitness;
   model y = x3 x1 / seqb ss1 ss2;
      output out=model013 p=yhat r=resid;
title 'model with x0 x1 and x3';
proc plot data=model013;
   plot resid*yhat / vref=0;
   plot resid*x3 / vref=0;
   plot resid*x1 / vref=0;
proc print data=model013;
   var y x1 x3 yhat resid;
proc reg data=fitness;
   model y = x3 x5 / seqb ss1 ss2;
      output out=model035 p=yhat r=resid;
title 'model with x0 x3 and x5';
proc plot data=model035;
   plot resid*yhat / vref=0;
   plot resid*x3 / vref=0;
   plot resid*x5 / vref=0;
proc print data=model035;
   var y x3 x5 yhat resid;
proc reg data=fitness;
   model y = x3 x5 x1 / seqb ss1 ss2;
      output out=model0135 p=yhat r=resid;
title 'model with x0 x1 x3 and x5';
proc plot data=model0135;
   plot resid*yhat / vref=0;
   plot resid*x1 / vref=0;
   plot resid*x3 / vref=0;
   plot resid*x5 / vref=0;
proc print data=model0135;
   var y x1 x3 x5 yhat resid;
proc univariate data=model0135 plot normal;
     var resid;
proc rank data=model0135 normal=blom out=new2;
     var resid;
     ranks normsc;
proc print data=new2;
   var resid normsc;
proc plot data=new2;
     plot resid*normsc;
proc reg data=fitness;
   model y = x3 x5 x6 / seqb ss1 ss2;
      output out=model0356 p=yhat r=resid;
title 'model with x0 x3 x5 and x6';
proc plot data=model0356;
   plot resid*yhat / vref=0;
   plot resid*x3 / vref=0;
   plot resid*x5 / vref=0;
   plot resid*x6 / vref=0;
proc print data=model0356;
   var y x3 x5 x6 yhat resid;
run;