data crd;
input Replicate	Trt $ Yield;
datalines;
1 A 23	
1 B 42	
1 C 47
2 A 36
2 B 26
2 C 43
3 A 31
3 B 47
3 C 43
4 A 33
4 B 34
4 C 39
;;
data crdsub;
set crd;
if trt='A' or trt='B';
proc print;
title 'Output of a Subset of the Data';
run;