title 'Ancova, distinct X for each Y';
*-- Winer/Brown/Michaels p 833;
data tab1036;
  input subj  group $ x1 y1 x2 y2;
datalines;
1 A1  3  8  4 14
2 A1  5 11  9 18
3 A1 11 16 14 22
4 A2  2  6  1  8
5 A2  8 12  9 14
6 A2 10  9  9 10
7 A3  7 10  4 10
8 A3  8 14 10 18
9 A3  9 15 12 22
;
*-- change to univariate format;
data tab;
   set tab1036;
   drop x1 x2 y1 y2;
   x = x1; y = y1; b=1; output;
   x = x2; y = y2; b=2; output;
proc glm data=tab;
   class group b subj;
   model y = x group b group*b subj(group);
   test h=group  e=subj(group);