DATA A; INPUT A B Y; CARDS; 1 1 20.2 1 1 20.8 1 2 20.7 1 2 21.6 1 3 19.7 1 3 21.0 2 1 19.9 2 1 20.5 2 2 21.7 2 2 20.6 2 3 18.9 2 3 20.1 3 1 21.3 3 1 22.5 3 2 23.0 3 2 21.9 3 3 23.6 3 3 24.8 ; PROC GLM; CLASSES A B; MODEL Y=A|B; RUN;