Multivariate Analysis of Covariance

This example concerns a one way layout with 45 patients in 4 groups (defined by body type and obesity status). There are 4 biochemical measurements made on the urine of each subject: three are treated as response variables and one as a covariate, the specific gravity of the urine.

The issue is to look for group differences adjusting and not adjusting for the covariate specific gravity.

run;
    data long;
    infile 'dq5.1';
    input group creatin chloride choline specgrav;
run;
proc print;
run;
proc glm;
    class group;
    model creatin chloride choline = group|specgrav;
    manova h= group*specgrav / printh printe;
run;
proc glm;
    class group;
    model creatin chloride choline = group specgrav;
    manova h= group / printh printe;
    means group / bon scheffe tukey;
run;
proc glm;
    class group;
    model creatin chloride choline = group;
    manova h= group / printh printe;
    means group / bon scheffe tukey;
run;

Here are som conclusions based on the output below:

  1. The group by specific gravity interaction appears to be marginally significant so that adjusting for specific gravity comparisons is difficult. In what follows we ignore the possibility of any such interaction.
  2. Adjusted for the specific gravity of the urine the overall P-value for the test of no group effect is about 1 to 2 percent so that there is fairly clearly a difference between groups.
  3. Without adjusting for the specific gravity the overall P-value is about the same.
  4. Natural parameters to examine with confidence intervals are all of the 3x(4 choose 2) = 18 differences in two means. The natural simultaneous intervals are either Bonferroni or Roy type. SAS produces univariate simultaneous confidence intervals easily but not the Roy type intervals. For Bonferroni intervals the individual intervals are t type based on df=N-p=45-4=41 unadjusted for specific gravity or 40 degrees of freedom adjusted for specific gravity.

                OBS    GROUP    CREATIN    CHLORIDE    CHOLINE    SPECGRAV

                  1      1        17.6        5.15        7.5        24
                  2      1        13.4        5.75        7.1        32
                  3      1        20.3        4.35        2.3        17
                  4      1        22.3        7.55        4.0        30
                  5      1        20.5        8.50        2.0        30
                  6      1        18.5       10.25        2.0        27
                  7      1        12.1        5.95       16.8        25
                  8      1        12.0        6.30       14.5        30
                  9      1        10.1        5.45        0.9        28
                 10      1        14.7        3.75        2.0        24
                 11      1        14.8        5.10        0.4        26
                 12      1        14.4        4.05        3.8        27
                 13      2        18.1        9.00       14.5        31
                 14      2        19.7        5.30       12.5        23
                 15      2        16.9        9.85        8.0        32
                 16      2        23.7        3.60        4.9        20
                 17      2        19.2        4.05        0.2        18
                 18      2        18.0        4.40        3.6        23
                 19      2        14.8        7.15       12.0        31
                 20      2        15.6        7.25        5.2        28
                 21      2        16.2        5.30       10.2        21
                 22      2        14.1        3.10        8.5        20
                 23      2        17.5        2.40        9.6        15
                 24      2        14.1        4.25        6.9        26
                 25      2        19.1        5.80        4.7        24
                 26      2        22.5        1.55        3.5        16
                 27      3        17.0        4.55        1.9        18
                 28      3        12.5        2.65        0.7        10
                 29      3        21.5        6.50        8.3        33
                 30      3        22.2        4.85        9.3        25
                 31      3        13.0        8.75       13.0        35
                 32      3        13.0        5.20       18.3        33
                 33      3        10.9       4.75        10.5        31
                 34      3        12.0       5.85        14.5        34
                 35      3        22.8       2.85         3.3        16
                 36      3        16.5       6.55         6.3        31
                 37      3        18.4       6.60         4.9        28
                 38      4        12.5       2.90        22.5        32
                 39      4         8.7       3.00        19.5        25
                 40      4         9.4       3.40         1.3        28
                 41      4        15.0       5.40        20.0        27
                 42      4        12.9       4.45         1.0        23
                 43      4        12.1       4.30         5.0        25
                 44      4        13.2       5.00         3.0        26
                 45      4        11.5       3.40         5.1        34
                              General Linear Models Procedure
                                  Class Level Information

                                Class    Levels    Values

                                GROUP         4    1 2 3 4


                          Number of observations in data set = 45


                              General Linear Models Procedure

Dependent Variable: CREATIN

Source                  DF     Sum of Squares           Mean Square  F Value    Pr > F

Model                    7       219.55914002           31.36559143     2.53    0.0311

Error                   37       458.27997109           12.38594516

Corrected Total         44       677.83911111

                  R-Square               C.V.              Root MSE       CREATIN Mean

                  0.323910           22.14057            3.51936715        15.89555556


Source                  DF          Type I SS           Mean Square  F Value    Pr > F

GROUP                    3       181.07035029           60.35678343     4.87    0.0059
SPECGRAV                 1        33.55457614           33.55457614     2.71    0.1082
SPECGRAV*GROUP           3         4.93421359            1.64473786     0.13    0.9399

Source                  DF        Type III SS           Mean Square  F Value    Pr > F

GROUP                    3        14.02852999            4.67617666     0.38    0.7697
SPECGRAV                 1        15.99112366           15.99112366     1.29    0.2632
SPECGRAV*GROUP           3         4.93421359            1.64473786     0.13    0.9399
                              General Linear Models Procedure

Dependent Variable: CHLORIDE

Source                  DF     Sum of Squares           Mean Square  F Value    Pr > F

Model                    7       114.69580798           16.38511543    10.42    0.0001

Error                   37        58.19619202            1.57287005

Corrected Total         44       172.89200000

                  R-Square               C.V.              Root MSE      CHLORIDE Mean

                  0.663396           23.90358            1.25414116         5.24666667


Source                  DF          Type I SS           Mean Square  F Value    Pr > F

GROUP                    3        20.03772646            6.67924215     4.25    0.0112
SPECGRAV                 1        68.81231628           68.81231628    43.75    0.0001
SPECGRAV*GROUP       3            25.84576523            8.61525508     5.48    0.0032

Source              DF            Type III SS           Mean Square  F Value    Pr > F

GROUP                3            18.50717670            6.16905890     3.92    0.0158
SPECGRAV             1            22.66541545           22.66541545    14.41    0.0005
SPECGRAV*GROUP       3            25.84576523            8.61525508     5.48    0.0032
                          General Linear Models Procedure

Dependent Variable: CHOLINE

Source              DF         Sum of Squares           Mean Square  F Value    Pr > F

Model                7           382.31484760           54.61640680     1.75    0.1269

Error               37          1153.34515240           31.17149061

Corrected Total     44          1535.66000000

              R-Square                   C.V.              Root MSE       CHOLINE Mean

              0.248958               74.77424            5.58314343         7.46666667


Source              DF              Type I SS           Mean Square  F Value    Pr > F

GROUP                3           103.80568182           34.60189394     1.11    0.3574
SPECGRAV             1           254.70756080          254.70756080     8.17    0.0070
SPECGRAV*GROUP       3            23.80160497            7.93386832     0.25    0.8576

Source              DF            Type III SS           Mean Square  F Value    Pr > F

GROUP                3            17.32050967            5.77350322     0.19    0.9058
SPECGRAV             1           129.17662849          129.17662849     4.14    0.0490
SPECGRAV*GROUP       3            23.80160497            7.93386832     0.25    0.8576



                          General Linear Models Procedure
                         Multivariate Analysis of Variance

                              E = Error SS&CP Matrix

                             CREATIN          CHLORIDE           CHOLINE

          CREATIN       458.27997109      63.446754032      -141.3962534
          CHLORIDE      63.446754032      58.196192023      -30.41709806
          CHOLINE       -141.3962534      -30.41709806      1153.3451524
                          General Linear Models Procedure
                         Multivariate Analysis of Variance

     Partial Correlation Coefficients from the Error SS&CP Matrix / Prob > |r|

                     DF = 37      CREATIN  CHLORIDE   CHOLINE

                     CREATIN     1.000000  0.388505 -0.194488
                                   0.0001    0.0145    0.2355

                     CHLORIDE    0.388505  1.000000 -0.117406
                                   0.0145    0.0001    0.4766

                     CHOLINE    -0.194488 -0.117406  1.000000
                                   0.2355    0.4766    0.0001



                          General Linear Models Procedure
                         Multivariate Analysis of Variance

                   H = Type III SS&CP Matrix for SPECGRAV*GROUP

                             CREATIN          CHLORIDE           CHOLINE

          CREATIN       4.9342135916      -10.88755514       8.822735835
          CHLORIDE      -10.88755514      25.845765234      -15.74572547
          CHOLINE        8.822735835      -15.74572547      23.801604973


             Characteristic Roots and Vectors of: E Inverse * H, where
       H = Type III SS&CP Matrix for SPECGRAV*GROUP   E = Error SS&CP Matrix

   Characteristic   Percent                Characteristic Vector  V'EV=1
        Root
                                          CREATIN       CHLORIDE        CHOLINE

     0.6025909825     97.71           -0.02637071     0.13956526    -0.00315708
     0.0141014522      2.29            0.01487276     0.02486753     0.02918876
     0.0000178077      0.00            0.04151186     0.01358309    -0.00641201



                          General Linear Models Procedure
                         Multivariate Analysis of Variance

                  Manova Test Criteria and F Approximations for
                the Hypothesis of no Overall SPECGRAV*GROUP Effect
       H = Type III SS&CP Matrix for SPECGRAV*GROUP   E = Error SS&CP Matrix

                              S=3    M=-0.5    N=16.5

  Statistic                     Value          F       Num DF     Den DF   Pr > F

  Wilks' Lambda              0.61530177     2.0939          9   85.33141   0.0387
  Pillai's Trace             0.38993364     1.8426          9        111   0.0683
  Hotelling-Lawley Trace     0.61671024     2.3070          9        101   0.0211
  Roy's Greatest Root        0.60259098     7.4320          3         37   0.0005

           NOTE: F Statistic for Roy's Greatest Root is an upper bound.



                          General Linear Models Procedure
                              Class Level Information

                            Class    Levels    Values

                            GROUP         4    1 2 3 4


                      Number of observations in data set = 45


                          General Linear Models Procedure

Dependent Variable: CREATIN

Source              DF         Sum of Squares           Mean Square  F Value    Pr > F

Model                4           214.62492643           53.65623161     4.63    0.0036

Error               40           463.21418468           11.58035462

Corrected Total     44           677.83911111

              R-Square                   C.V.              Root MSE       CREATIN Mean

              0.316631               21.40845            3.40299201        15.89555556


Source              DF              Type I SS           Mean Square  F Value    Pr > F

GROUP                3           181.07035029           60.35678343     5.21    0.0039
SPECGRAV             1            33.55457614           33.55457614     2.90    0.0965

Source              DF            Type III SS           Mean Square  F Value    Pr > F

GROUP                3           142.67640002           47.55880001     4.11    0.0124
SPECGRAV             1            33.55457614           33.55457614     2.90    0.0965
                          General Linear Models Procedure

Dependent Variable: CHLORIDE

Source              DF         Sum of Squares           Mean Square  F Value    Pr > F

Model                4            88.85004274           22.21251069    10.57    0.0001

Error               40            84.04195726            2.10104893

Corrected Total     44           172.89200000

              R-Square                   C.V.              Root MSE      CHLORIDE Mean

              0.513905               27.62706            1.44949955         5.24666667


Source              DF              Type I SS           Mean Square  F Value    Pr > F

GROUP                3            20.03772646            6.67924215     3.18    0.0342
SPECGRAV             1            68.81231628           68.81231628    32.75    0.0001

Source              DF            Type III SS           Mean Square  F Value    Pr > F

GROUP                3            28.32353333            9.44117778     4.49    0.0083
SPECGRAV             1            68.81231628           68.81231628    32.75    0.0001
                          General Linear Models Procedure

Dependent Variable: CHOLINE

Source              DF         Sum of Squares           Mean Square  F Value    Pr > F

Model                4           358.51324262           89.62831066     3.05    0.0278

Error               40          1177.14675738           29.42866893

Corrected Total     44          1535.66000000

              R-Square                   C.V.              Root MSE       CHOLINE Mean

              0.233459               72.65384            5.42481971         7.46666667


Source              DF              Type I SS           Mean Square  F Value    Pr > F

GROUP                3           103.80568182           34.60189394     1.18    0.3310
SPECGRAV             1           254.70756080          254.70756080     8.66    0.0054

Source              DF            Type III SS           Mean Square  F Value    Pr > F

GROUP                3           111.34065943           37.11355314     1.26    0.3007
SPECGRAV             1           254.70756080          254.70756080     8.66    0.0054



                          General Linear Models Procedure
                         Multivariate Analysis of Variance

                              E = Error SS&CP Matrix

                             CREATIN          CHLORIDE           CHOLINE

          CREATIN       463.21418468      52.559198888      -132.5735176
          CHLORIDE      52.559198888      84.041957257      -46.16282353
          CHOLINE       -132.5735176      -46.16282353      1177.1467574
                          General Linear Models Procedure
                         Multivariate Analysis of Variance

     Partial Correlation Coefficients from the Error SS&CP Matrix / Prob > |r|

                     DF = 40      CREATIN  CHLORIDE   CHOLINE

                     CREATIN     1.000000  0.266385 -0.179536
                                   0.0001    0.0882    0.2553

                     CHLORIDE    0.266385  1.000000 -0.146767
                                   0.0882    0.0001    0.3537

                     CHOLINE    -0.179536 -0.146767  1.000000
                                   0.2553    0.3537    0.0001



                          General Linear Models Procedure
                         Multivariate Analysis of Variance

                        H = Type III SS&CP Matrix for GROUP

                             CREATIN          CHLORIDE           CHOLINE

          CREATIN       142.67640002      57.975991093      -25.81759754
          CHLORIDE      57.975991093      28.323533332       -31.2952734
          CHOLINE       -25.81759754       -31.2952734      111.34065943


             Characteristic Roots and Vectors of: E Inverse * H, where
           H = Type III SS&CP Matrix for GROUP   E = Error SS&CP Matrix

   Characteristic   Percent                Characteristic Vector  V'EV=1
        Root
                                          CREATIN       CHLORIDE        CHOLINE

     0.4876676013     79.60            0.02827764     0.07153539     0.00101538
     0.1204865877     19.67            0.02648038    -0.03977179     0.02501754
     0.0044972823      0.73           -0.02957063     0.07905405     0.01614189



                          General Linear Models Procedure
                         Multivariate Analysis of Variance

  Manova Test Criteria and F Approximations for the Hypothesis of no Overall GROUP Effect
           H = Type III SS&CP Matrix for GROUP   E = Error SS&CP Matrix

                               S=3    M=-0.5    N=18

  Statistic                     Value          F       Num DF     Den DF   Pr > F

  Wilks' Lambda              0.59722595     2.4280          9   92.63262   0.0159
  Pillai's Trace             0.43981457     2.2905          9        120   0.0208
  Hotelling-Lawley Trace     0.61265147     2.4960          9        110   0.0123
  Roy's Greatest Root        0.48766760     6.5022          3         40   0.0011

           NOTE: F Statistic for Roy's Greatest Root is an upper bound.



                          General Linear Models Procedure

            Tukey's Studentized Range (HSD) Test for variable: CREATIN

            NOTE: This test controls the type I experimentwise error rate.

               Alpha= 0.05  Confidence= 0.95  df= 40  MSE= 11.58035
                    Critical Value of Studentized Range= 3.791

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              2    - 3          -2.199       1.476       5.151
              2    - 1          -1.659       1.930       5.518
              2    - 4           1.866       5.909       9.952   ***

              3    - 2          -5.151      -1.476       2.199
              3    - 1          -3.354       0.454       4.261
              3    - 4           0.195       4.433       8.671   ***

              1    - 2          -5.518      -1.930       1.659
              1    - 3          -4.261      -0.454       3.354
              1    - 4          -0.184       3.979       8.143

              4    - 2          -9.952      -5.909      -1.866   ***
              4    - 3          -8.671      -4.433      -0.195   ***
              4    - 1          -8.143      -3.979       0.184


                          General Linear Models Procedure

                  Bonferroni (Dunn) T tests for variable: CREATIN

            NOTE: This test controls the type I experimentwise error rate but
                  generally has a higher type II error rate than Tukey's for all
                  pairwise comparisons.

               Alpha= 0.05  Confidence= 0.95  df= 40  MSE= 11.58035
                           Critical Value of T= 2.77587

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              2    - 3          -2.330       1.476       5.282
              2    - 1          -1.786       1.930       5.646
              2    - 4           1.722       5.909      10.096   ***

              3    - 2          -5.282      -1.476       2.330
              3    - 1          -3.489       0.454       4.397
              3    - 4           0.044       4.433       8.822   ***

              1    - 2          -5.646      -1.930       1.786
              1    - 3          -4.397      -0.454       3.489
              1    - 4          -0.332       3.979       8.291

              4    - 2         -10.096      -5.909      -1.722   ***
              4    - 3          -8.822      -4.433      -0.044   ***
              4    - 1          -8.291      -3.979       0.332

                          General Linear Models Procedure

                       Scheffe's test for variable: CREATIN

            NOTE: This test controls the type I experimentwise error rate but
                  generally has a higher type II error rate than Tukey's for all
                  pairwise comparisons.

               Alpha= 0.05  Confidence= 0.95  df= 40  MSE= 11.58035
                           Critical Value of F= 2.83875

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              2    - 3          -2.525       1.476       5.477
              2    - 1          -1.977       1.930       5.837
              2    - 4           1.508       5.909      10.310   ***

              3    - 2          -5.477      -1.476       2.525
              3    - 1          -3.692       0.454       4.599
              3    - 4          -0.181       4.433       9.047

              1    - 2          -5.837      -1.930       1.977
              1    - 3          -4.599      -0.454       3.692
              1    - 4          -0.554       3.979       8.512

              4    - 2         -10.310      -5.909      -1.508   ***
              4    - 3          -9.047      -4.433       0.181
              4    - 1          -8.512      -3.979       0.554

                          General Linear Models Procedure

            Tukey's Studentized Range (HSD) Test for variable: CHLORIDE

            NOTE: This test controls the type I experimentwise error rate.

               Alpha= 0.05  Confidence= 0.95  df= 40  MSE= 2.101049
                    Critical Value of Studentized Range= 3.791

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              1    - 3         -0.9820      0.6398      2.2616
              1    - 2         -0.7302      0.7982      2.3267
              1    - 4          0.2579      2.0312      3.8046   ***

              3    - 1         -2.2616     -0.6398      0.9820
              3    - 2         -1.4070      0.1584      1.7239
              3    - 4         -0.4139      1.3915      3.1968

              2    - 1         -2.3267     -0.7982      0.7302
              2    - 3         -1.7239     -0.1584      1.4070
              2    - 4         -0.4889      1.2330      2.9550

              4    - 1         -3.8046     -2.0312     -0.2579   ***
              4    - 3         -3.1968     -1.3915      0.4139
              4    - 2         -2.9550     -1.2330      0.4889


                          General Linear Models Procedure

                 Bonferroni (Dunn) T tests for variable: CHLORIDE

            NOTE: This test controls the type I experimentwise error rate but
                  generally has a higher type II error rate than Tukey's for all
                  pairwise comparisons.

               Alpha= 0.05  Confidence= 0.95  df= 40  MSE= 2.101049
                           Critical Value of T= 2.77587

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              1    - 3         -1.0398      0.6398      2.3193
              1    - 2         -0.7847      0.7982      2.3811
              1    - 4          0.1947      2.0312      3.8678   ***

              3    - 1         -2.3193     -0.6398      1.0398
              3    - 2         -1.4627      0.1584      1.7796
              3    - 4         -0.4781      1.3915      3.2611

              2    - 1         -2.3811     -0.7982      0.7847
              2    - 3         -1.7796     -0.1584      1.4627
              2    - 4         -0.5502      1.2330      3.0163

              4    - 1         -3.8678     -2.0312     -0.1947   ***
              4    - 3         -3.2611     -1.3915      0.4781
              4    - 2         -3.0163     -1.2330      0.5502

                          General Linear Models Procedure

                       Scheffe's test for variable: CHLORIDE

            NOTE: This test controls the type I experimentwise error rate but
                  generally has a higher type II error rate than Tukey's for all
                  pairwise comparisons.

               Alpha= 0.05  Confidence= 0.95  df= 40  MSE= 2.101049
                           Critical Value of F= 2.83875

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              1    - 3         -1.1259      0.6398      2.4055
              1    - 2         -0.8659      0.7982      2.4623
              1    - 4          0.1005      2.0312      3.9620   ***

              3    - 1         -2.4055     -0.6398      1.1259
              3    - 2         -1.5459      0.1584      1.8628
              3    - 4         -0.5740      1.3915      3.3570

              2    - 1         -2.4623     -0.7982      0.8659
              2    - 3         -1.8628     -0.1584      1.5459
              2    - 4         -0.6417      1.2330      3.1078

              4    - 1         -3.9620     -2.0312     -0.1005   ***
              4    - 3         -3.3570     -1.3915      0.5740
              4    - 2         -3.1078     -1.2330      0.6417

                          General Linear Models Procedure

            Tukey's Studentized Range (HSD) Test for variable: CHOLINE

            NOTE: This test controls the type I experimentwise error rate.

               Alpha= 0.05  Confidence= 0.95  df= 40  MSE= 29.42867
                    Critical Value of Studentized Range= 3.791

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              4    - 3          -5.354       1.402       8.159
              4    - 2          -4.220       2.225       8.670
              4    - 1          -2.237       4.400      11.037

              3    - 4          -8.159      -1.402       5.354
              3    - 2          -5.036       0.823       6.681
              3    - 1          -3.072       2.998       9.067

              2    - 4          -8.670      -2.225       4.220
              2    - 3          -6.681      -0.823       5.036
              2    - 1          -3.545       2.175       7.895

              1    - 4         -11.037      -4.400       2.237
              1    - 3          -9.067      -2.998       3.072
              1    - 2          -7.895      -2.175       3.545


                          General Linear Models Procedure

                  Bonferroni (Dunn) T tests for variable: CHOLINE

            NOTE: This test controls the type I experimentwise error rate but
                  generally has a higher type II error rate than Tukey's for all
                  pairwise comparisons.

               Alpha= 0.05  Confidence= 0.95  df= 40  MSE= 29.42867
                           Critical Value of T= 2.77587

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              4    - 3          -5.595       1.402       8.399
              4    - 2          -4.449       2.225       8.899
              4    - 1          -2.473       4.400      11.273

              3    - 4          -8.399      -1.402       5.595
              3    - 2          -5.245       0.823       6.890
              3    - 1          -3.288       2.998       9.284

              2    - 4          -8.899      -2.225       4.449
              2    - 3          -6.890      -0.823       5.245
              2    - 1          -3.749       2.175       8.099

              1    - 4         -11.273      -4.400       2.473
              1    - 3          -9.284      -2.998       3.288
              1    - 2          -8.099      -2.175       3.749

                          General Linear Models Procedure

                       Scheffe's test for variable: CHOLINE

            NOTE: This test controls the type I experimentwise error rate but
                  generally has a higher type II error rate than Tukey's for all
                  pairwise comparisons.

               Alpha= 0.05  Confidence= 0.95  df= 40  MSE= 29.42867
                           Critical Value of F= 2.83875

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              4    - 3          -5.954       1.402       8.758
              4    - 2          -4.791       2.225       9.241
              4    - 1          -2.826       4.400      11.626

              3    - 4          -8.758      -1.402       5.954
              3    - 2          -5.556       0.823       7.201
              3    - 1          -3.611       2.998       9.606

              2    - 4          -9.241      -2.225       4.791
              2    - 3          -7.201      -0.823       5.556
              2    - 1          -4.053       2.175       8.403

              1    - 4         -11.626      -4.400       2.826
              1    - 3          -9.606      -2.998       3.611
              1    - 2          -8.403      -2.175       4.053

                          General Linear Models Procedure
                              Class Level Information

                            Class    Levels    Values

                            GROUP         4    1 2 3 4


                      Number of observations in data set = 45


                          General Linear Models Procedure

Dependent Variable: CREATIN

Source              DF         Sum of Squares           Mean Square  F Value    Pr > F

Model                3           181.07035029           60.35678343     4.98    0.0049

Error               41           496.76876082           12.11631124

Corrected Total     44           677.83911111

              R-Square                   C.V.              Root MSE       CREATIN Mean

              0.267129               21.89825            3.48084921        15.89555556


Source              DF              Type I SS           Mean Square  F Value    Pr > F

GROUP                3           181.07035029           60.35678343     4.98    0.0049

Source              DF            Type III SS           Mean Square  F Value    Pr > F

GROUP                3           181.07035029           60.35678343     4.98    0.0049
                          General Linear Models Procedure

Dependent Variable: CHLORIDE

Source              DF         Sum of Squares           Mean Square  F Value    Pr > F

Model                3            20.03772646            6.67924215     1.79    0.1639

Error               41           152.85427354            3.72815301

Corrected Total     44           172.89200000

              R-Square                   C.V.              Root MSE      CHLORIDE Mean

              0.115897               36.80132            1.93084257         5.24666667


Source              DF              Type I SS           Mean Square  F Value    Pr > F

GROUP                3            20.03772646            6.67924215     1.79    0.1639

Source              DF            Type III SS           Mean Square  F Value    Pr > F

GROUP                3            20.03772646            6.67924215     1.79    0.1639
                          General Linear Models Procedure

Dependent Variable: CHOLINE

Source              DF         Sum of Squares           Mean Square  F Value    Pr > F

Model                3           103.80568182           34.60189394     0.99    0.4067

Error               41          1431.85431818           34.92327605

Corrected Total     44          1535.66000000

              R-Square                   C.V.              Root MSE       CHOLINE Mean

              0.067597               79.14632            5.90959187         7.46666667


Source              DF              Type I SS           Mean Square  F Value    Pr > F

GROUP                3           103.80568182           34.60189394     0.99    0.4067

Source              DF            Type III SS           Mean Square  F Value    Pr > F

GROUP                3           103.80568182           34.60189394     0.99    0.4067



                          General Linear Models Procedure
                         Multivariate Analysis of Variance

                              E = Error SS&CP Matrix

                             CREATIN          CHLORIDE           CHOLINE

          CREATIN       496.76876082      4.5074756494      -225.0213636
          CHLORIDE      4.5074756494      152.85427354      86.226818182
          CHOLINE       -225.0213636      86.226818182      1431.8543182
                          General Linear Models Procedure
                         Multivariate Analysis of Variance

     Partial Correlation Coefficients from the Error SS&CP Matrix / Prob > |r|

                     DF = 41      CREATIN  CHLORIDE   CHOLINE

                     CREATIN     1.000000  0.016358 -0.266807
                                   0.0001    0.9171    0.0837

                     CHLORIDE    0.016358  1.000000  0.184312
                                   0.9171    0.0001    0.2367

                     CHOLINE    -0.266807  0.184312  1.000000
                                   0.0837    0.2367    0.0001



                          General Linear Models Procedure
                         Multivariate Analysis of Variance

                        H = Type III SS&CP Matrix for GROUP

                             CREATIN          CHLORIDE           CHOLINE

          CREATIN       181.07035029      40.036857684      -66.72530303
          CHLORIDE      40.036857684      20.037726461      -41.37181818
          CHOLINE       -66.72530303      -41.37181818      103.80568182


             Characteristic Roots and Vectors of: E Inverse * H, where
           H = Type III SS&CP Matrix for GROUP   E = Error SS&CP Matrix

   Characteristic   Percent                Characteristic Vector  V'EV=1
        Root
                                          CREATIN       CHLORIDE        CHOLINE

     0.4336849273     74.76            0.03815241     0.03717808    -0.00338557
     0.1409699628     24.30            0.02655774    -0.05607206     0.02113111
     0.0054156726      0.93           -0.00409794     0.04773387     0.01799753



                          General Linear Models Procedure
                         Multivariate Analysis of Variance

  Manova Test Criteria and F Approximations for the Hypothesis of no Overall GROUP Effect
           H = Type III SS&CP Matrix for GROUP   E = Error SS&CP Matrix

                              S=3    M=-0.5    N=18.5

  Statistic                     Value          F       Num DF     Den DF   Pr > F

  Wilks' Lambda              0.60803198     2.3959          9   95.06636   0.0171
  Pillai's Trace             0.43143592     2.2956          9        123   0.0203
  Hotelling-Lawley Trace     0.58007056     2.4277          9        113   0.0147
  Roy's Greatest Root        0.43368493     5.9270          3         41   0.0019

           NOTE: F Statistic for Roy's Greatest Root is an upper bound.



                          General Linear Models Procedure

            Tukey's Studentized Range (HSD) Test for variable: CREATIN

            NOTE: This test controls the type I experimentwise error rate.

               Alpha= 0.05  Confidence= 0.95  df= 41  MSE= 12.11631
                    Critical Value of Studentized Range= 3.787

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              2    - 3          -2.279       1.476       5.231
              2    - 1          -1.737       1.930       5.596
              2    - 4           1.778       5.909      10.040   ***

              3    - 2          -5.231      -1.476       2.279
              3    - 1          -3.437       0.454       4.344
              3    - 4           0.102       4.433       8.764   ***

              1    - 2          -5.596      -1.930       1.737
              1    - 3          -4.344      -0.454       3.437
              1    - 4          -0.275       3.979       8.233

              4    - 2         -10.040      -5.909      -1.778   ***
              4    - 3          -8.764      -4.433      -0.102   ***
              4    - 1          -8.233      -3.979       0.275


                          General Linear Models Procedure

                  Bonferroni (Dunn) T tests for variable: CREATIN

            NOTE: This test controls the type I experimentwise error rate but
                  generally has a higher type II error rate than Tukey's for all
                  pairwise comparisons.

               Alpha= 0.05  Confidence= 0.95  df= 41  MSE= 12.11631
                           Critical Value of T= 2.77235

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              2    - 3          -2.412       1.476       5.364
              2    - 1          -1.867       1.930       5.726
              2    - 4           1.632       5.909      10.186   ***

              3    - 2          -5.364      -1.476       2.412
              3    - 1          -3.574       0.454       4.482
              3    - 4          -0.051       4.433       8.917

              1    - 2          -5.726      -1.930       1.867
              1    - 3          -4.482      -0.454       3.574
              1    - 4          -0.426       3.979       8.384

              4    - 2         -10.186      -5.909      -1.632   ***
              4    - 3          -8.917      -4.433       0.051
              4    - 1          -8.384      -3.979       0.426

                          General Linear Models Procedure

                       Scheffe's test for variable: CREATIN

            NOTE: This test controls the type I experimentwise error rate but
                  generally has a higher type II error rate than Tukey's for all
                  pairwise comparisons.

               Alpha= 0.05  Confidence= 0.95  df= 41  MSE= 12.11631
                           Critical Value of F= 2.83275

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              2    - 3          -2.612       1.476       5.564
              2    - 1          -2.062       1.930       5.922
              2    - 4           1.412       5.909      10.406   ***

              3    - 2          -5.564      -1.476       2.612
              3    - 1          -3.782       0.454       4.690
              3    - 4          -0.282       4.433       9.148

              1    - 2          -5.922      -1.930       2.062
              1    - 3          -4.690      -0.454       3.782
              1    - 4          -0.652       3.979       8.611

              4    - 2         -10.406      -5.909      -1.412   ***
              4    - 3          -9.148      -4.433       0.282
              4    - 1          -8.611      -3.979       0.652

                          General Linear Models Procedure

            Tukey's Studentized Range (HSD) Test for variable: CHLORIDE

            NOTE: This test controls the type I experimentwise error rate.

               Alpha= 0.05  Confidence= 0.95  df= 41  MSE= 3.728153
                    Critical Value of Studentized Range= 3.787

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              1    - 3         -1.5183      0.6398      2.7979
              1    - 2         -1.2357      0.7982      2.8321
              1    - 4         -0.3286      2.0312      4.3911

              3    - 1         -2.7979     -0.6398      1.5183
              3    - 2         -1.9246      0.1584      2.2415
              3    - 4         -1.0108      1.3915      3.7938

              2    - 1         -2.8321     -0.7982      1.2357
              2    - 3         -2.2415     -0.1584      1.9246
              2    - 4         -1.0584      1.2330      3.5244

              4    - 1         -4.3911     -2.0312      0.3286
              4    - 3         -3.7938     -1.3915      1.0108
              4    - 2         -3.5244     -1.2330      1.0584


                          General Linear Models Procedure

                 Bonferroni (Dunn) T tests for variable: CHLORIDE

            NOTE: This test controls the type I experimentwise error rate but
                  generally has a higher type II error rate than Tukey's for all
                  pairwise comparisons.

               Alpha= 0.05  Confidence= 0.95  df= 41  MSE= 3.728153
                           Critical Value of T= 2.77235

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              1    - 3         -1.5947      0.6398      2.8742
              1    - 2         -1.3076      0.7982      2.9041
              1    - 4         -0.4120      2.0312      4.4745

              3    - 1         -2.8742     -0.6398      1.5947
              3    - 2         -1.9983      0.1584      2.3152
              3    - 4         -1.0958      1.3915      3.8788

              2    - 1         -2.9041     -0.7982      1.3076
              2    - 3         -2.3152     -0.1584      1.9983
              2    - 4         -1.1394      1.2330      3.6055

              4    - 1         -4.4745     -2.0312      0.4120
              4    - 3         -3.8788     -1.3915      1.0958
              4    - 2         -3.6055     -1.2330      1.1394

                          General Linear Models Procedure

                       Scheffe's test for variable: CHLORIDE

            NOTE: This test controls the type I experimentwise error rate but
                  generally has a higher type II error rate than Tukey's for all
                  pairwise comparisons.

               Alpha= 0.05  Confidence= 0.95  df= 41  MSE= 3.728153
                           Critical Value of F= 2.83275

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              1    - 3         -1.7098      0.6398      2.9893
              1    - 2         -1.4161      0.7982      3.0125
              1    - 4         -0.5379      2.0312      4.6004

              3    - 1         -2.9893     -0.6398      1.7098
              3    - 2         -2.1094      0.1584      2.4263
              3    - 4         -1.2240      1.3915      4.0069

              2    - 1         -3.0125     -0.7982      1.4161
              2    - 3         -2.4263     -0.1584      2.1094
              2    - 4         -1.2616      1.2330      3.7277

              4    - 1         -4.6004     -2.0312      0.5379
              4    - 3         -4.0069     -1.3915      1.2240
              4    - 2         -3.7277     -1.2330      1.2616

                          General Linear Models Procedure

            Tukey's Studentized Range (HSD) Test for variable: CHOLINE

            NOTE: This test controls the type I experimentwise error rate.

               Alpha= 0.05  Confidence= 0.95  df= 41  MSE= 34.92328
                    Critical Value of Studentized Range= 3.787

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              4    - 3          -5.950       1.402       8.755
              4    - 2          -4.788       2.225       9.238
              4    - 1          -2.822       4.400      11.622

              3    - 4          -8.755      -1.402       5.950
              3    - 2          -5.553       0.823       7.198
              3    - 1          -3.607       2.998       9.603

              2    - 4          -9.238      -2.225       4.788
              2    - 3          -7.198      -0.823       5.553
              2    - 1          -4.050       2.175       8.400

              1    - 4         -11.622      -4.400       2.822
              1    - 3          -9.603      -2.998       3.607
              1    - 2          -8.400      -2.175       4.050


                          General Linear Models Procedure

                  Bonferroni (Dunn) T tests for variable: CHOLINE

            NOTE: This test controls the type I experimentwise error rate but
                  generally has a higher type II error rate than Tukey's for all
                  pairwise comparisons.

               Alpha= 0.05  Confidence= 0.95  df= 41  MSE= 34.92328
                           Critical Value of T= 2.77235

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              4    - 3          -6.210       1.402       9.015
              4    - 2          -5.036       2.225       9.486
              4    - 1          -3.078       4.400      11.878

              3    - 4          -9.015      -1.402       6.210
              3    - 2          -5.778       0.823       7.424
              3    - 1          -3.841       2.998       9.837

              2    - 4          -9.486      -2.225       5.036
              2    - 3          -7.424      -0.823       5.778
              2    - 1          -4.270       2.175       8.620

              1    - 4         -11.878      -4.400       3.078
              1    - 3          -9.837      -2.998       3.841
              1    - 2          -8.620      -2.175       4.270

                          General Linear Models Procedure

                       Scheffe's test for variable: CHOLINE

            NOTE: This test controls the type I experimentwise error rate but
                  generally has a higher type II error rate than Tukey's for all
                  pairwise comparisons.

               Alpha= 0.05  Confidence= 0.95  df= 41  MSE= 34.92328
                           Critical Value of F= 2.83275

         Comparisons significant at the 0.05 level are indicated by '***'.

                             Simultaneous            Simultaneous
                                 Lower    Difference     Upper
                 GROUP        Confidence    Between   Confidence
               Comparison        Limit       Means       Limit

              4    - 3          -6.603       1.402       9.407
              4    - 2          -5.410       2.225       9.860
              4    - 1          -3.463       4.400      12.263

              3    - 4          -9.407      -1.402       6.603
              3    - 2          -6.118       0.823       7.764
              3    - 1          -4.193       2.998      10.189

              2    - 4          -9.860      -2.225       5.410
              2    - 3          -7.764      -0.823       6.118
              2    - 1          -4.602       2.175       8.952

              1    - 4         -12.263      -4.400       3.463
              1    - 3         -10.189      -2.998       4.193
              1    - 2          -8.952      -2.175       4.602


Richard Lockhart
Tue Feb 17 22:46:33 PST 1998