options nodate nonumber ps=55 ls=80;

title 'RPD -- Example 3.1 -- Y=Yield, X=Ozone';

proc iml;

X={1 0.02, 1 0.07, 1 0.11, 1 0.15};

Y={242, 237, 231, 201};

XPX=X`*X;

XPY=X`*Y;

XPXINV=inv(XPX);

BETAHAT=XPXINV*XPY;

P=X*XPXINV*X`;

YHAT=P*Y;

I4=i(4);

e=(I4-P)*Y;

print X Y XPX XPY XPXINV;

print BETAHAT P YHAT e;

run;