data temp;
set sasuser.fitness;
c = 1;
run;

proc iml;

use temp;

read  all var { c age weight} into x;
read  all var {runtime} into y;
print x;
print y;

xt = t(x);
xtx = xt*x;
xtx_i = inv(xtx);
xty = xt*y;
beta1 = xtx_i*xty;
beta = inv(t(x)*x)*t(x)*y;
print beta1;
print beta;