* drill2.sas, drill advance experiment, Table 7.12 (page 226);
* Voss-Wang method of analysis;
options ls=72;
;
DATA DRILL;
  INPUT A B C D  ADV;
  Y=LOG10(ADV);   *  log to base 10;
  LINES;
  1 1 1 1   1.68
  1 1 1 2   2.07
  1 1 2 1   4.98
  1 1 2 2   7.77
  1 2 1 1   3.28
  1 2 1 2   4.09
  1 2 2 1   9.97
  1 2 2 2  11.75
  2 1 1 1   1.98
  2 1 1 2   2.44
  2 1 2 1   5.70
  2 1 2 2   9.43
  2 2 1 1   3.44
  2 2 1 2   4.53
  2 2 2 1   9.07
  2 2 2 2  16.30
;
*  Calculate contrast coefficients for m contrasts and print them;
DATA DRILL2;     SET DRILL;
    A=2*A-3;   B=2*B-3;   C=2*C-3;   D=2*D-3;
   AB=A*B;    AC=A*C;    AD=A*D;    BC=B*C;     BD=B*D;   CD=C*D;
  ABC=AB*C;  ABD=AB*D;  ACD=AC*D;  BCD=BC*D;  ABCD=ABC*D;
;
*  Data set DRILL contains the original data;
DATA DRILL4;  SET DRILL;
*  Fit complete model including all main effects and interactions;
PROC GLM;
  CLASSES A B C D;
  MODEL Y = A | B | C | D;
;
*  Data set DRILL2 contains the contrast coefficients and observations;
DATA DRILL5;  SET DRILL2;
*  Calculate quasi mean squares for the Voss-Wang method as follows;
*  Omit the d=8 smallest contrasts.  The resulting mean squared error
*  is the msQ for confidence intervals for the m-d=7 largest contrasts;
PROC GLM;
  CLASSES A B C D;
  MODEL Y = C B D A CD AD ACD;
;
*  Omit the d=8 smallest contrasts apart from ABD. The resulting mean 
*  squared error is the msQ for confidence intervals for ABD;
PROC GLM;
  CLASSES A B C D;
  MODEL Y = C B D A CD AD ABD;
;
*  Omit the d=8 smallest contrasts apart from BC. The resulting mean 
*  squared error is the msQ for confidence intervals for BC;
PROC GLM;
  CLASSES A B C D;
  MODEL Y = C B D A CD AD BC;
;
*  etc for each contrast in turn;