options nocenter ls=75;goptions colors=(none);

data new;
 input cow period trt resp @@;
cards;
 1 1 1 38 1 2 2 32 1 3 3 35 1 4 4 33
 2 1 2 39 2 2 3 37 2 3 4 36 2 4 1 30
 3 1 3 45 3 2 4 38 3 3 1 37 3 4 2 35
 4 1 4 41 4 2 1 30 4 3 2 32 4 4 3 33
;

proc glm;
class cow trt period;
model resp=trt period cow;
means trt/ lines tukey; 
means period cow; 
output out=new1 r=res p=pred;

symbol1 v=circle;
proc gplot; plot res*pred;

proc univariate noprint; 
histogram res / normal (L=1 mu=0 sigma=est) kernel (L=2);
run;