UCLA Academic Technology Services HomeServicesClassesContactJobs
Search

SAS Textbook Examples
Applied Linear Statistical Models by Neter, Kutner, et. al.
Chapter 28: Nested Designs, Subsampling, and Partially Nested Designs

Inputting training school data, table 28.1, p. 1122.
data training;
  input score A B classes;
  label A = 'School'
        B = 'Instructor';
cards;
  25  1  1  1
  29  1  1  2
  14  1  2  1
  11  1  2  2
  11  2  1  1
   6  2  1  2
  22  2  2  1
  18  2  2  2
  17  3  1  1
  20  3  1  2
   5  3  2  1
   2  3  2  2
;
run;
Obtaining the factor means and the grand mean, table 28.1, p. 1122. Using proc glm is more efficient than using multiple proc means.
Note: The score mean in the output is the grand mean.
proc glm data=training;
  class A B;
  model score = A B;
  means A B;
run;
quit;
The GLM Procedure

<output omitted>

R-Square     Coeff Var      Root MSE    score Mean
0.345300      52.78363      7.917544      15.00000

<output omitted>

Level of           ------------score------------
A            N             Mean          Std Dev
1            4       19.7500000       8.61684397
2            4       14.2500000       7.13559154
3            4       11.0000000       8.83176087
Level of           ------------score------------
B            N             Mean          Std Dev
1            6       18.0000000       8.57904424
2            6       12.0000000       7.61577311
Fig. 28.3, p. 1130.
data plot;
  set training;
  if b=1 then b1 = score;
  if b=2 then b2 = score;
run;
goptions reset=all;
 
symbol1 v=dot c=blue h=.8;
symbol2 v=circle c=red h=.8;
axis1 label=('Score');
axis2 order=(1 to 3 by 1) value=('Atlanta (i=1)' 'Chicago (i=2)' 'San Francisco (i=3)')
      label=(a=90 'School') offset=(5,2);
legend1 label=none value=(height=.8 font=swiss 'Instructor j=1' 'Instructor j=2' ) 
        position=(bottom right inside) mode=protect cborder=black;
proc gplot data=plot;
  plot a*(b1 b2)/ overlay legend=legend1 haxis=axis1 vaxis=axis2;
run;
quit;
Nested two-factor ANOVA for the Training School data, table 28.4a, p. 1130.
proc glm data=training;
  class A B;
  model score = A B(A);
run;
quit;
The GLM Procedure

   Class Level Information

Class         Levels    Values
A                  3    1 2 3
B                  2    1 2

Number of observations    12
The GLM Procedure
Dependent Variable: score
                                        Sum of
Source                      DF         Squares     Mean Square    F Value    Pr > F
Model                        5     724.0000000     144.8000000      20.69    0.0010
Error                        6      42.0000000       7.0000000
Corrected Total             11     766.0000000

R-Square     Coeff Var      Root MSE    score Mean
0.945170      17.63834      2.645751      15.00000

Source                      DF       Type I SS     Mean Square    F Value    Pr > F
A                            2     156.5000000      78.2500000      11.18    0.0095
B(A)                         3     567.5000000     189.1666667      27.02    0.0007
Source                      DF     Type III SS     Mean Square    F Value    Pr > F
A                            2     156.5000000      78.2500000      11.18    0.0095
B(A)                         3     567.5000000     189.1666667      27.02    0.0007
Decomposition of SSB(A), table 28.4b, p. 1130.
Note: Due to the large amount of output the SSB(Ai) have been italicized to make it easier to recognize them.
proc glm data=training;
  by A;
  class B ;
  model score = B;
run;
quit;
School=1

The GLM Procedure

   Class Level Information

Class         Levels    Values
B                  2    1 2

Number of observations    4
School=1

The GLM Procedure
Dependent Variable: score
                                        Sum of
Source                      DF         Squares     Mean Square    F Value    Pr > F
Model                        1     210.2500000     210.2500000      33.64    0.0285
Error                        2      12.5000000       6.2500000
Corrected Total              3     222.7500000

R-Square     Coeff Var      Root MSE    score Mean
0.943883      12.65823      2.500000      19.75000

Source                      DF       Type I SS     Mean Square    F Value    Pr > F
B                            1     210.2500000     210.2500000      33.64    0.0285
Source                      DF     Type III SS     Mean Square    F Value    Pr > F
B                            1     210.2500000     210.2500000      33.64    0.0285
School=2

The GLM Procedure

   Class Level Information

Class         Levels    Values
B                  2    1 2

Number of observations    4
School=2

The GLM Procedure
Dependent Variable: score
                                        Sum of
Source                      DF         Squares     Mean Square    F Value    Pr > F
Model                        1     132.2500000     132.2500000      12.90    0.0695
Error                        2      20.5000000      10.2500000
Corrected Total              3     152.7500000

R-Square     Coeff Var      Root MSE    score Mean
0.865794      22.46710      3.201562      14.25000

Source                      DF       Type I SS     Mean Square    F Value    Pr > F
B                            1     132.2500000     132.2500000      12.90    0.0695
Source                      DF     Type III SS     Mean Square    F Value    Pr > F
B                            1     132.2500000     132.2500000      12.90    0.0695
School=3

The GLM Procedure

   Class Level Information

Class         Levels    Values
B                  2    1 2

Number of observations    4
School=3

The GLM Procedure
Dependent Variable: score
                                        Sum of
Source                      DF         Squares     Mean Square    F Value    Pr > F
Model                        1     225.0000000     225.0000000      50.00    0.0194
Error                        2       9.0000000       4.5000000
Corrected Total              3     234.0000000

R-Square     Coeff Var      Root MSE    score Mean
0.961538      19.28473      2.121320      11.00000

Source                      DF       Type I SS     Mean Square    F Value    Pr > F
B                            1     225.0000000     225.0000000      50.00    0.0194
Source                      DF     Type III SS     Mean Square    F Value    Pr > F
B                            1     225.0000000     225.0000000      50.00    0.0194
Testing for factor B differences within level of factor A, specifically testing for instructor differences within the Atlanta School, comments bottom of p. 1132.
ods listing close;
ods output  GLM.ANOVA.score.OverallANOVA=anova;
proc glm data=training;
  class A B;
  model score = A B(A);
run;
quit;
ods output GLM.ByGroup1.ANOVA.score.OverallANOVA=anova1;
proc glm data=training;
  by A;
  class B ;
  model score = B;
run;
quit;
ods listing;
ods output close;
data _null_;
  set anova;
  if source='Error' then call symput('mse', ms);
  if source='Error' then call symput('dfe', df);
run;
%put here are the macros: &mse and &dfe;
data _null_;
  set anova1;
  if source='Model' then call symput('msb_a1', ms);
  if source='Model' then call symput('dfb_a1', df);
run;
%put here are the macros: &msb_a1 and &dfb_a1;
data temp;
  F = &msb_a1 / &mse ;
  Fcrit = finv( .95, &dfb_a1, &dfe);
  p_value = 1 - probf(F, &dfb_a1, &dfe);
run;
proc print data=temp;
run;
Obs       F        Fcrit       p_value

 1     30.0357    5.98738    .001542714
Examining the residual of the nested model for the Training School data, fig. 28.4a, p. 1134.
proc glm data=training noprint;
  class A B;
  model score = A B(A);
  output out=resids r=resid;
run;
quit;
data resids;
  set resids;
  if a=1 then resid1=resid;
  if a=2 then resid2=resid;
  if a=3 then resid3=resid;
run;
 
symbol1 c=blue v=dot h=.8;
symbol2 c=red v=circle h=.8;
symbol3 c=green v=star h=.8;
axis1 label=('Residuals');
axis2 value=('Atlanta' 'Chicago' 'San Francisco');
proc gplot data=resids;
  plot a*(resid1 resid2 resid3)/ overlay vaxis=axis2 haxis=axis1;
run;
quit;
Normal probability plot of the residuals from the nested model, fig. 28.4b, p. 1134.
proc capability data=resids noprint;
   qqplot resid;
run;
Estimating the mean learning score for each school and calculating a 95% confidence coefficient the mean learning score for the Atlanta school (a=1)with , p. 1135.
Note: The lsmean statement for B(A) gives the confidence interval using the Bonferroni coefficient for all possible comparisons (6 choose 2 = 6!/2!4! = 30 )(B = t(1-.01/2*30, 6) = 7.31444) hence the confidence intervals are much larger.
proc glm data=training;
  class a b;
  model score = a b(a);
  lsmeans A / cl adjust=tukey;
  lsmeans A / pdiff adjust=tukey cl alpha=.1;
  lsmeans B(A) / pdiff adjust=bon cl;
run;
quit;
The GLM Procedure

<output omitted>

Least Squares Means

A    score LSMEAN

1      19.7500000
2      14.2500000
3      11.0000000


A    score LSMEAN      95% Confidence Limits

1       19.750000       16.513040    22.986960
2       14.250000       11.013040    17.486960
3       11.000000        7.763040    14.236960


<output omitted>

       Least Squares Means for effect A
     Pr > |t| for H0: LSMean(i)=LSMean(j)

          Dependent Variable: score

i/j              1             2             3
   1                      0.0586        0.0081
   2        0.0586                      0.2677
   3        0.0081        0.2677

<output omitted>

          Least Squares Means for Effect A

            Difference         Simultaneous 90%
               Between      Confidence Limits for
i    j           Means       LSMean(i)-LSMean(j)
1    2        5.500000        0.792778    10.207222
1    3        8.750000        4.042778    13.457222
2    3        3.250000       -1.457222     7.957222

The GLM Procedure
Least Squares Means
Adjustment for Multiple Comparisons: Bonferroni

                            LSMEAN
B    A    score LSMEAN      Number
1    1      27.0000000           1
2    1      12.5000000           2
1    2       8.5000000           3
2    2      20.0000000           4
1    3      18.5000000           5
2    3       3.5000000           6

<output omitted>

B    A    score LSMEAN      95% Confidence Limits

1    1       27.000000       22.422247    31.577753
2    1       12.500000        7.922247    17.077753
1    2        8.500000        3.922247    13.077753
2    2       20.000000       15.422247    24.577753
1    3       18.500000       13.922247    23.077753
2    3        3.500000       -1.077753     8.077753

        Least Squares Means for Effect B(A)

            Difference         Simultaneous 95%
               Between      Confidence Limits for
i    j           Means       LSMean(i)-LSMean(j)

1    2       14.500000        2.070465    26.929535
1    3       18.500000        6.070465    30.929535
1    4        7.000000       -5.429535    19.429535
1    5        8.500000       -3.929535    20.929535
1    6       23.500000       11.070465    35.929535
2    3        4.000000       -8.429535    16.429535
2    4       -7.500000      -19.929535     4.929535
2    5       -6.000000      -18.429535     6.429535

The GLM Procedure
Least Squares Means
Adjustment for Multiple Comparisons: Bonferroni

        Least Squares Means for Effect B(A)

            Difference         Simultaneous 95%
               Between      Confidence Limits for
i    j           Means       LSMean(i)-LSMean(j)

2    6        9.000000       -3.429535    21.429535
3    4      -11.500000      -23.929535     0.929535
3    5      -10.000000      -22.429535     2.429535
3    6        5.000000       -7.429535    17.429535
4    5        1.500000      -10.929535    13.929535
4    6       16.500000        4.070465    28.929535
5    6       15.000000        2.570465    27.429535
Testing three specific comparisons of treatment means: mu11-mu12, mu21-mu22, mu31-mu32, p. 1137.
It is a little tricky figuring out which difference of means correspond to the i and j columns in the last two tables in the output above. The numbers for i and j refer to the list of the six lsmeans in the table with the lsmean score before the two tables with confidence intervals in the above output. So, for the i=1, j=2 difference the second mean in the list (which is mu12) is begin subtracted from the first mean in the list (which is mu11). Similarly, the i=3, j=4 difference is the fourth mean (mu22) being subtracted from the third mean (mu21).
ods listing close;
ods output GLM.LSMEANS.B_A_.score.LSMeanDiffCL=means  GLM.ANOVA.score.OverallANOVA=anova;
proc glm data=training;
  class a b;
  model score = a b(a);
  lsmeans B(A) / pdiff adjust=bon cl;
run;
quit;
ods listing;
ods output close;
data _null_;
  set anova;
  if source='Error' then call symput('mse', ms);
run;
%put here is the mse &mse; /* check number in SAS log file*/
data temp;
  set means;
  drop effect dependent LowerCL UpperCL;
  B = tinv(1 - (.01/2*3), 6);
  s2L = &mse*2/2; 
  BsL = B*sqrt(s2L);
  lower = difference - BsL;
  upper = difference + BsL;
run;
proc print data=temp;
  where (i=1 and j=2) or (i=3 and j=4) or (i=5 and j=6); 
  var difference B s2L BsL lower upper;
run;
Obs      Difference       B       s2L      BsL        lower       upper

  1       14.500000    2.82893     7     7.48464      7.0154     21.9846
 10      -11.500000    2.82893     7     7.48464    -18.9846     -4.0154
 15       15.000000    2.82893     7     7.48464      7.5154     22.4846
Estimating the overall mean with a 95% confidence interval, p. 1137.
ods listing close;
ods output  OverallANOVA=anova  FitStatistics=fit;
proc glm data=training;
  class a b;
  model score = a b(a);
run;
quit;
ods output close;
ods listing;
data _null_;
  set anova;
  if source='Error' then call symput('mse', ms);
  if source='Error' then call symput('dfe', df);
  if source='Corrected Total' then call symput('df', df);
run;
%put here are the macros &mse &dfe &df; /*Check number in SAS log file*/
data _null_;
  set fit;
  call symput('mean', Depmean);
run;
%put here is the mean &mean; /*Check number in SAS log file*/
data temp;
  mean = &mean;
  s2Y = &mse/(&df+1);
  sY = sqrt(s2Y);
  t = tinv(.975, &dfe);
  lower = mean-t*sY;
  upper = mean + t*sY;
run;
proc print data=temp;
run;
Obs    mean      s2Y         sY         t        lower      upper

 1      15     0.58333    0.76376    2.44691    13.1311    16.8689
Inputting Follow-up Training School study, table 28.6a, p. 1139.
data followup;
  input score A B rep;
  label A='School' 
        B='Instructor';
cards;
  20  1  1  1
  22  1  1  2
   8  1  2  1
   9  1  3  1
  13  1  3  2
   4  2  1  1
   8  2  1  2
  16  2  2  1
  20  2  2  2
;
run;
Generating the X and Y variables to be used in the regression, table 28.4b, p. 1139.
data reg;
  set followup;
  x1=1;
  if A=2 then x1=-1;
  x2=0;
  if A=1 and B=1 then x2=1;
  else if A=1 and B=3 then x2=-1;
  x3=0;
  if A=1 and B=2 then x3=1;
  else if A=1 and B=3 then x3=-1;
  x4=0;
  if A=2 and B=1 then x4=1;
  if A=2 and B=2 then x4=-1;
run;
The output from the tests statements correspond to the MS and Ftest statistics in table 28.7, p. 1141.
proc reg data=reg;
  model score = x1-x4;
  main_A: test x1=0;
  instructor_effect: test x2=x3=x4=0;
run;
quit; 
The REG Procedure
Model: MODEL1
Dependent Variable: score

                             Analysis of Variance

                                    Sum of           Mean
Source                   DF        Squares         Square    F Value    Pr > F
Model                     4      308.00000       77.00000      11.85    0.0172
Error                     4       26.00000        6.50000
Corrected Total           8      334.00000

Root MSE              2.54951    R-Square     0.9222
Dependent Mean       13.33333    Adj R-Sq     0.8443
Coeff Var            19.12132

                        Parameter Estimates

                     Parameter       Standard
Variable     DF       Estimate          Error    t Value    Pr > |t|
Intercept     1       12.66667        0.87599      14.46      0.0001
x1            1        0.66667        0.87599       0.76      0.4890
x2            1        7.66667        1.58990       4.82      0.0085
x3            1       -5.33333        1.90029      -2.81      0.0485
x4            1       -6.00000        1.27475      -4.71      0.0093

The REG Procedure
Model: MODEL1

    Test main_A Results for Dependent Variable score

                                Mean
Source             DF         Square    F Value    Pr > F
Numerator           1        3.76471       0.58    0.4890
Denominator         4        6.50000

The REG Procedure
Model: MODEL1

             Test instructor_effect Results
              for Dependent Variable score

                                Mean
Source             DF         Square    F Value    Pr > F
Numerator           3       98.40000      15.14    0.0119
Denominator         4        6.50000
You can obtain the same results using proc glm and the option ss3 which is robust to unequal sample sizes, table 28.7, p. 1141.
proc glm data=followup;
  class a b;
  model score= a b(a) / ss3;
run;
quit;
The GLM Procedure

   Class Level Information

Class         Levels    Values
A                  2    1 2
B                  3    1 2 3

Number of observations    9
The GLM Procedure
Dependent Variable: score
                                        Sum of
Source                      DF         Squares     Mean Square    F Value    Pr > F
Model                        4     308.0000000      77.0000000      11.85    0.0172
Error                        4      26.0000000       6.5000000
Corrected Total              8     334.0000000

R-Square     Coeff Var      Root MSE    score Mean
0.922156      19.12132      2.549510      13.33333

Source                      DF     Type III SS     Mean Square    F Value    Pr > F
A                            1       3.7647059       3.7647059       0.58    0.4890
B(A)                         3     295.2000000      98.4000000      15.14    0.0119
Inputting the Bread Crustiness data, table 28.9, p. 1144.
data bread;
  input score a b rep;
  label a ='Temperature'
        b ='Batch'
      rep ='Exp. unit';
cards;
   4  1  1  1
   7  1  1  2
   5  1  1  3
  12  1  2  1
   8  1  2  2
  10  1  2  3
  14  2  1  1
  13  2  1  2
  11  2  1  3
   9  2  2  1
  10  2  2  2
  12  2  2  3
  14  3  1  1
  17  3  1  2
  15  3  1  3
  16  3  2  1
  19  3  2  2
  18  3  2  3
;
run;
Fig. 28.5, p. 1144.
data plot;
  set bread;
  if b=1 then b1=score;
  if b=2 then b2=score;
run;
goptions reset=all;

symbol1 c=blue v=dot;
symbol2 c=red v=circle;
axis1 value=('Low (i=1)' 'Medium (i=2)' 'High (i=3)' ) offset=(2,5);
axis2 label=('Crustiness') order=(0 to 20 by 5);
legend1 label=none value=(height=.8 font=swiss 'Batch=1' 'Batch=2' ) 
        position=(top left inside) mode=share cborder=black;
proc gplot data=plot;
  plot a*(b1 b2)/ overlay vaxis=axis1 haxis=axis2 legend=legend1;
run;
quit;
ANOVA table 28.10, and tests of temperature effect and batch differences, p. 1144-1145. Estimating treatment effects, including the mean of the low temperature group and the difference between the low and high temperature groups with a 95% confidence interval, p. 1146.
proc glm data=bread;
  class a b;
  model score = a b(a);
  random b(a);
  temperature_effect: test h=a e=b(a);
  lsmeans a / e=b(a) pdiff cl;
run;
quit;
The GLM Procedure

   Class Level Information

Class         Levels    Values
a                  3    1 2 3
b                  2    1 2

Number of observations    18
The GLM Procedure
Dependent Variable: score
                                        Sum of
Source                      DF         Squares     Mean Square    F Value    Pr > F
Model                        5     284.4444444      56.8888889      21.79    <.0001
Error                       12      31.3333333       2.6111111
Corrected Total             17     315.7777778

R-Square     Coeff Var      Root MSE    score Mean
0.900774      13.59163      1.615893      11.88889

Source                      DF       Type I SS     Mean Square    F Value    Pr > F
a                            2     235.4444444     117.7222222      45.09    <.0001
b(a)                         3      49.0000000      16.3333333       6.26    0.0084
Source                      DF     Type III SS     Mean Square    F Value    Pr > F
a                            2     235.4444444     117.7222222      45.09    <.0001
b(a)                         3      49.0000000      16.3333333       6.26    0.0084

The GLM Procedure

Source                  Type III Expected Mean Square
a                       Var(Error) + 3 Var(b(a)) + Q(a)
b(a)                    Var(Error) + 3 Var(b(a))

The GLM Procedure
Least Squares Means
Standard Errors and Probabilities Calculated Using the Type III MS for b(a) as an Error Term

                       LSMEAN
a    score LSMEAN      Number
1       7.6666667           1
2      11.5000000           2
3      16.5000000           3

       Least Squares Means for effect a
     Pr > |t| for H0: LSMean(i)=LSMean(j)

          Dependent Variable: score

i/j              1             2             3
   1                      0.1990        0.0323
   2        0.1990                      0.1215
   3        0.0323        0.1215
   
a    score LSMEAN      95% Confidence Limits
1        7.666667        2.415898    12.917435
2       11.500000        6.249231    16.750769
3       16.500000       11.249231    21.750769

          Least Squares Means for Effect a

            Difference
               Between    95% Confidence Limits for
i    j           Means       LSMean(i)-LSMean(j)
1    2       -3.833333      -11.259041     3.592375
1    3       -8.833333      -16.259041    -1.407625
2    3       -5.000000      -12.425708     2.425708

NOTE: To ensure overall protection level, only probabilities associated with pre-planned
      comparisons should be used.

The GLM Procedure

Dependent Variable: score

        Tests of Hypotheses Using the Type III MS for b(a) as an Error Term

Source                      DF     Type III SS     Mean Square    F Value    Pr > F
a                            2     235.4444444     117.7222222       7.21    0.0715
Tests of the main effects of temperature, p. 1144-1145. Estimating treatment effects, including the mean of the low temperature group and the difference between the low and high temperature groups with a 95% confidence intervals using proc mixed, p. 1146.
proc mixed data=bread;
  class a b;
  model score = a;
  random b(a);
  lsmeans a / cl pdiff;
run;
quit;
The Mixed Procedure

                  Model Information
Data Set                     WORK.BREAD
Dependent Variable           score
Covariance Structure         Variance Components
Estimation Method            REML
Residual Variance Method     Profile
Fixed Effects SE Method      Model-Based
Degrees of Freedom Method    Containment

             Class Level Information

Class    Levels    Values
a             3    1 2 3
b             2    1 2

            Dimensions
Covariance Parameters             2
Columns in X                      4
Columns in Z                      6
Subjects                          1
Max Obs Per Subject              18
Observations Used                18
Observations Not Used             0
Total Observations               18

                     Iteration History

Iteration    Evaluations    -2 Res Log Like       Criterion
        0              1        73.11545106
        1              1        67.84036856      0.00000000

                   Convergence criteria met.
Covariance Parameter
      Estimates

Cov Parm     Estimate
b(a)           4.5741
Residual       2.6111

The Mixed Procedure

           Fit Statistics
-2 Res Log Likelihood            67.8
AIC (smaller is better)          71.8
AICC (smaller is better)         72.8
BIC (smaller is better)          71.4

        Type 3 Tests of Fixed Effects

              Num     Den
Effect         DF      DF    F Value    Pr > F
a               2       3       7.21    0.0715

                                    Least Squares Means

                               Standard
Effect  Temperature  Estimate     Error    DF  t Value  Pr > |t|   Alpha     Lower     Upper
a       1              7.6667    1.6499     3     4.65    0.0188    0.05    2.4159   12.9174
a       2             11.5000    1.6499     3     6.97    0.0061    0.05    6.2492   16.7508
a       3             16.5000    1.6499     3    10.00    0.0021    0.05   11.2492   21.7508

                             Differences of Least Squares Means

                                                Standard
Effect   Temperature   Temperature   Estimate      Error     DF   t Value   Pr > |t|    Alpha
a        1             2              -3.8333     2.3333      3     -1.64     0.1990     0.05
a        1             3              -8.8333     2.3333      3     -3.79     0.0323     0.05
a        2             3              -5.0000     2.3333      3     -2.14     0.1215     0.05

           Differences of Least Squares Means

Effect   Temperature   Temperature      Lower       Upper
a        1             2             -11.2590      3.5924
a        1             3             -16.2590     -1.4076
a        2             3             -12.4257      2.4257
Unable to reproduce the same results as in the book for the estimation of sigma-squared (between batch variability), p. 1146-1147.
Inputting the Group Decision Making data, table 28.12, p. 1152.
data decision;
  input score a b c rep ;
  label a ='Nationality'
        b ='Size'
	c ='Observer';
cards;
  16  1  1  1  1
  20  1  1  1  2
  14  1  1  2  1
  19  1  1  2  2
   7  2  1  1  1
   5  2  1  1  2
   4  2  1  2  1
   9  2  1  2  2
  21  1  2  1  1
  25  1  2  1  2
  28  1  2  2  1
  19  1  2  2  2
  11  2  2  1  1
  17  2  2  1  2
  12  2  2  2  1
  15  2  2  2  2
;
run;
Fig. 28.6, p. 1152.
data plot;
  set decision;
  if a=1 and c=1 then a1c1=score;
  if a=1 and c=2 then a1c2=score;
  if a=2 and c=1 then a2c1=score;
  if a=2 and c=2 then a2c2=score;
run;
goptions reset=all;
 
symbol1 c=red v=square;
symbol2 c=green v=circle;
symbol3 c=blue v=:;
symbol4 c=cyan v=dot;
axis1 label=(a=90 'Size of Team') value=('4' '8') offset=(10,5) order=(1 2);
axis2 label=('Number of Group Interactions');
legend1 label=none value=(height=.8 font=swiss 'US, observer 1' 'US, observer 2' 
        'Foreign, observer 1' 'Foreign, observer 2' ) across=2 
        position=(bottom right inside) mode=share cborder=black;
proc gplot data=plot;
  plot b*(a1c1 a1c2 a2c1 a2c2) / overlay vaxis=axis1 haxis=axis2 legend=legend1; 
run;
quit;
Fig. 28.7, p. 1153 and estimating the difference in mean score between US and Foreign teams, p. 1154.
proc glm data=decision;
  class a b c;
  model score = A | c(A) | b;
  test h=a e=c(a);
  lsmeans a / e=c(a) cl pdiff;
run;
quit;
The GLM Procedure

   Class Level Information

Class         Levels    Values
a                  2    1 2
b                  2    1 2
c                  2    1 2

Number of observations    16
The GLM Procedure
Dependent Variable: score

                                        Sum of
Source                      DF         Squares     Mean Square    F Value    Pr > F
Model                        7     607.7500000      86.8214286       6.55    0.0083
Error                        8     106.0000000      13.2500000
Corrected Total             15     713.7500000

R-Square     Coeff Var      Root MSE    score Mean
0.851489      24.06648      3.640055      15.12500

Source                      DF       Type I SS     Mean Square    F Value    Pr > F
a                            1     420.2500000     420.2500000      31.72    0.0005
c(a)                         2       0.5000000       0.2500000       0.02    0.9814
b                            1     182.2500000     182.2500000      13.75    0.0060
a*b                          1       2.2500000       2.2500000       0.17    0.6911
b*c(a)                       2       2.5000000       1.2500000       0.09    0.9110

Source                      DF     Type III SS     Mean Square    F Value    Pr > F
a                            1     420.2500000     420.2500000      31.72    0.0005
c(a)                         2       0.5000000       0.2500000       0.02    0.9814
b                            1     182.2500000     182.2500000      13.75    0.0060
a*b                          1       2.2500000       2.2500000       0.17    0.6911
b*c(a)                       2       2.5000000       1.2500000       0.09    0.9110

        Tests of Hypotheses Using the Type III MS for c(a) as an Error Term

Source                      DF     Type III SS     Mean Square    F Value    Pr > F
a                            1     420.2500000     420.2500000    1681.00    0.0006

The GLM Procedure
Least Squares Means
Standard Errors and Probabilities Calculated Using the Type III MS for c(a) as an Error Term

                     H0:LSMean1=
                       LSMean2
a    score LSMEAN       Pr > |t|
1      20.2500000         0.0006
2      10.0000000
a    score LSMEAN      95% Confidence Limits
1       20.250000       19.489391    21.010609
2       10.000000        9.239391    10.760609

          Least Squares Means for Effect a

            Difference
               Between    95% Confidence Limits for
i    j           Means       LSMean(i)-LSMean(j)
1    2       10.250000        9.174337    11.325663

How to cite this page

Report an error on this page

UCLA Researchers are invited to our Statistical Consulting Services
We recommend others to our list of Other Resources for Statistical Computing Help
These pages are Copyrighted (c) by UCLA Academic Technology Services


The content of this web site should not be construed as an endorsement of any particular web site, book, or software product by the University of California