options nocenter ls=80;

data example1;
  input trt x y @@;
  cards;
  1 1.2 7 1 1.9 13 1 3.4 16
  2 4.0 20 2 5.2 22 2 5.8 32
  3 7.7 31 3 8.3 45 3 8.9 42
  ;

proc sort; by trt;
symbol1 v=circle   i=  c=black;
symbol2 v=square   i=  c=black;
symbol3 v=triangle i=  c=black;
proc gplot;
  plot y*x=trt;
run;

proc glm; class trt;
 model y=trt;
 output out=resid r=resy;
proc glm; class trt;
 model x=trt;
 output out=resid1 r=resx;
proc glm; model resy=resx;
symbol1 v=circle i=rl;
proc gplot;
  plot resy*resx;
run;

proc glm data=example1;
 class trt;
 model y=trt x / solution;
 means trt /lines lsd;
 lsmeans trt / tdiff adjust=t;
run;