options nocenter ls=78;
goptions colors=(none);
symbol1 v=circle; axis1 offset=(5); 

data wash;
 input stain soap y @@;
 cards;
1 1 45 1 2 47 1 3 48 1 4 42
2 1 43 2 2 46 2 3 50 2 4 37
3 1 51 3 2 52 3 3 55 3 4 49
;

proc glm;
 class stain soap;
 model y = soap stain;
 means soap / tukey alpha=.01;
 output out=diag r=res p=pred;

/* Check Assumptions */
proc univariate noprint;
 qqplot res / normal (L=1 mu=0 sigma=est);
 hist res /normal (L=1 mu=0 sigma=est) kernel(L=2 K=quadratic);
run;

proc gplot;
 plot res*soap / haxis=axis1;
 plot res*stain / haxis=axis1;
 plot res*pred;
run;

data washr;
quit;