options ls=80; 

title1 'Orthogonal Polynomial Contrasts';

data one;
 infile 'c:\saswork\data\tensile.dat';
 input percent strength time;

 p2 = percent*percent;
 p3 = percent*p2;

proc glm data=one;
 class percent;
 model strength=percent;
 contrast 'linear' percent -2 -1 0 1 2;
 contrast 'quadratic' percent 2 -1 -2 -1 2;
 contrast 'cubic' percent -1 2 0 -2 1;
 contrast 'quartic' percent 1 -4 6 -4 1;

proc reg data=one;
 model strength = percent p2 p3;