OPTIONS LS=72;
TITLE 'EXAMPLE 25. ANALYSIS OF COVARIANCE: ORANGES DATA';
DATA ORANGES;
INPUT STORE DAYS P1 P2 Q1 Q2;
CARDS;
1   1   37   61  11.3208   0.0047
1   2   37   37  12.9151   0.0037
1   3   45   53  18.8947   7.5429
1   4   41   41  14.6739   7.0652
1   5   57   41   8.6493  21.2085
1   6   49   33   9.5238  16.6667
2   1   49   49   7.6923   7.1154
2   2   53   53   0.0017   1.0000
2   3   53   45   8.0477  24.2176
2   4   53   53   6.7358   2.9361
2   5   61   37   6.1441  40.5720
2   6   49   65  21.7939   2.8324
3   1   53   45   4.2553   6.0284
3   2   57   57   0.0017   2.0906
3   3   49   49  11.0196  13.9329
3   4   53   53   6.2762   6.5551
3   5   53   45  13.2316  10.6870
3   6   53   53   5.0676   5.1351
4   1   57   57   5.6235   3.9120
4   2   49   49  14.9893   7.2805
4   3   53   53  13.7233  16.3105
4   4   53   45   6.0669  23.8494
4   5   53   53   8.1602   4.1543
4   6   61   37   1.4423  21.1538
5   1   45   45   6.9971   6.9971
5   2   53   45   5.2308   3.6923
5   3   57   57   8.2560  10.6679
5   4   49   49  14.5000  16.7500
5   5   53   53  20.7627  15.2542
5   6   53   45   3.6115  21.5442
6   1   53   53  11.3475   4.9645
6   2   53   45   9.4650  11.7824
6   3   53   53  22.6103  14.8897
6   4   61   37   0.0020  19.2000
6   5   49   65  20.5997   2.3468
6   6   37   37  28.1828  17.9543
;
PROC GLM;
CLASS STORE DAYS;
MODEL Q1=STORE DAYS P1 P2/SOLUTION;
LSMEANS DAYS/STDERR;
RUN;

PROC GLM;
CLASS DAYS;
MODEL Q1=DAYS P1 P2/SOLUTION;
LSMEANS DAYS/STDERR;
RUN;

PROC GLM;
CLASS DAYS;
MODEL Q1=DAYS P1 DAYS*P1/SOLUTION;
LSMEANS DAYS/STDERR;
RUN;