option ls=76 nocenter;
data ex_4_4;
  input resistance et wafer position;
  datalines;
5.22  1  1  1 x 
5.61  1  1  2 x
6.11  1  1  3 x 
6.33  1  1  4 x 
6.13  1  2  1 x 
6.14  1  2  2 x 
5.60  1  2  3 x 
5.91  1  2  4 x 
5.49  1  3  1 x 
4.60  1  3  2 x 
4.95  1  3  3 x 
5.42  1  3  4 x 
5.78  2  1  1 x
6.52  2  1  2 x
5.90  2  1  3 x
5.67  2  1  4 x
5.77  2  2  1 x
6.23  2  2  2 x
5.57  2  2  3 x
5.96  2  2  4 x
6.43  2  3  1 x
5.81  2  3  2 x
5.83  2  3  3 x
6.12  2  3  4 x
5.66  3  1  1 x
6.25  3  1  2 x
5.46  3  1  3 x
5.08  3  1  4 x
6.53  3  2  1 x 
6.50  3  2  2 x
6.23  3  2  3 x 
6.84  3  2  4 x 
6.22  3  3  1 x
6.29  3  3  2 x 
5.63  3  3  3 x 
6.36  3  3  4 x
6.75  4  1  1 x 
6.97  4  1  2 x 
6.02  4  1  3 x
6.88  4  1  4 x 
6.22  4  2  1 x 
6.54  4  2  2 x
6.12  4  2  3 x 
6.61  4  2  4 x 
6.05  4  3  1 x
6.15  4  3  2 x 
5.55  4  3  3 x
6.13  4  3  4 x
;

proc mixed data=ex_4_4;
   class wafer et position;
   model resistance=et|position / ddfm=satterth;
   random wafer(et);
   lsmeans position / diff;
   estimate 'pos1 vs pos3'       position 1 0 -1 0;
   contrast 'pos1 vs pos3'       position 1 0 -1 0;
   estimate 'pos 3 vs others'    position 1 1 -3 1 / divisor=3; 
   estimate 'pos3 v oth - wrong' position 1 1 -3 1; 
   contrast 'pos 3 vs others'    position 1 1 -3 1;
   ods select Estimates Contrasts Diffs;
run;