data rr;
	length group $ 9;
	input group $ outcome $ count;
datalines;
1-placebo mi 20
1-placebo no-mi 80
2-asprin mi 15
2-asprin no-mi 135
;
proc freq data=rr;
	title 'Program to compute a relative risk';
	tables group*outcome / CHM;
	weight count;
run;