SAS Textbook Examples
Applied Linear Statistical Models by Neter, Kutner, et. al.
Chapter 20: Analysis of Factor Effects in Two-Factor Studies-Equal Sample Sizes

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Inputting the Castle Bakery data, table 19.7, p. 818.
data bakery;
  input sales height width store;
cards;
  47  1  1  1
  43  1  1  2
  46  1  2  1
  40  1  2  2
  62  2  1  1
  68  2  1  2
  67  2  2  1
  71  2  2  2
  41  3  1  1
  39  3  1  2
  42  3  2  1
  46  3  2  2
;
run;
Fig. 20.2, p. 857. 
Note: The normal option with mean (mu) and standard deviation (sigma) specified will create the reference line. When specifying est for either mean or standard deviation or both SAS will estimate the best fit based on the data.
ods listing close;
proc glm data=bakery;
  class height width;
  model sales = height width height*width;
  means height width;
  ods output means = temp;
run;
quit;
ods listing;
ods output close;
goptions reset=all;
symbol1 c=blue v=dot h=.8;
proc capability data=temp noprint;
  where effect = 'height';
  qqplot  Mean_sales / normal(mu=51 sigma=3);
run;
axis1 order=(40 to 70 by 10);
symbol1 v=dot c=blue h=.8;
proc capability data=temp noprint;
  where effect = 'width';
  qqplot  Mean_sales / vaxis=axis1 normal(mu=est sigma=est);
run;
Table 20.1 and confidence intervals for main effects of height and for the interaction effects, p. 858-859.
Note: Even though we are only interested in the pair-wise tests and the various confidence intervals when we use proc glm we get a great deal more results in the output.  We are interested in the results of the lsmeans statements and these are located at the end of the output.  The results that were calculated in the book are italicized.
proc glm data=bakery;
  class height width;
  model sales = height width height*width;
  lsmeans height / pdiff adjust=tukey  cl;
  lsmeans height*width / cl;
run;
quit;
The GLM Procedure

   Class Level Information

Class         Levels    Values
height             3    1 2 3
width              2    1 2

Number of observations    12

The GLM Procedure

Dependent Variable: sales
                                        Sum of
Source                      DF         Squares     Mean Square    F Value    Pr > F
Model                        5     1580.000000      316.000000      30.58    0.0003
Error                        6       62.000000       10.333333
Corrected Total             11     1642.000000
R-Square     Coeff Var      Root MSE    sales Mean
0.962241      6.303040      3.214550      51.00000
Source                      DF       Type I SS     Mean Square    F Value    Pr > F
height                       2     1544.000000      772.000000      74.71    <.0001
width                        1       12.000000       12.000000       1.16    0.3226
height*width                 2       24.000000       12.000000       1.16    0.3747
Source                      DF     Type III SS     Mean Square    F Value    Pr > F
height                       2     1544.000000      772.000000      74.71    <.0001
width                        1       12.000000       12.000000       1.16    0.3226
height*width                 2       24.000000       12.000000       1.16    0.3747

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

                            LSMEAN
height    sales LSMEAN      Number
1           44.0000000           1
2           67.0000000           2
3           42.0000000           3
    Least Squares Means for effect height
     Pr > |t| for H0: LSMean(i)=LSMean(j)

          Dependent Variable: sales

i/j              1             2             3
   1                      0.0001        0.6714
   2        0.0001                      <.0001
   3        0.6714        <.000
height    sales LSMEAN      95% Confidence Limits
1            44.000000       40.067139    47.932861
2            67.000000       63.067139    70.932861
3            42.000000       38.067139    45.932861
       Least Squares Means for Effect height

            Difference         Simultaneous 95%
               Between      Confidence Limits for
i    j           Means       LSMean(i)-LSMean(j)
1    2      -23.000000      -29.973998   -16.026002
1    3        2.000000       -4.973998     8.973998
2    3       25.000000       18.026002    31.973998

The GLM Procedure
Least Squares Means

height    width    sales LSMEAN
1         1          45.0000000
1         2          43.0000000
2         1          65.0000000
2         2          69.0000000
3         1          40.0000000
3         2          44.0000000
height    width    sales LSMEAN      95% Confidence Limits
1         1           45.000000       39.438095    50.561905
1         2           43.000000       37.438095    48.561905
2         1           65.000000       59.438095    70.561905
2         2           69.000000       63.438095    74.561905
3         1           40.000000       34.438095    45.561905
3         2           44.000000       38.438095    49.561905
Table 20.3, p. 826.
data burr;
  input efficiency spacing speed;
cards;
  21.6  1.0  300
  22.3  1.0  400
  22.9  1.0  500
  18.7  1.2  300
  19.1  1.2  400
  21.6  1.2  500
  15.8  1.4  300
  17.9  1.4  400
  19.4  1.4  500
  13.2  1.6  300
  16.7  1.6  400
  19.5  1.6  500
;
run;
Fig. 20.5, p. 867.
Note: In order to get the lines on the same graph we need to create three variables for spacing that corresponds to each of the levels of speed. Likewise, we create four variables for speed corresponding to each of the levels for spacing. The overlay option in the plot statement lets us plot all the lines in the same graph.
data burr;
  set burr;
  if speed = 300 then rpm300 = spacing;
  if speed = 400 then rpm400 = spacing;
  if speed = 500 then rpm500 = spacing;
  if spacing = 1 then spac1 = speed;
  if spacing = 1.2 then spac12 = speed;
  if spacing = 1.4 then spac14 = speed;
  if spacing = 1.6 then spac16 = speed;
run;
goptions reset = all;
symbol1 v=dot c=blue h=.8 i=join;
symbol2 v=dot c=red h=.8 i=join;
symbol3 v=dot c=green h=.8 i=join;
symbol4 v=dot c=orange h=.8 i=join;
legend1 label=none value=(height=1 font=swiss '300 rpm' '400 rpm' '500 rpm' ) 
        position=(left bottom  inside) mode=share cborder=black;
axis1 label=('Spacing (units)');
legend2 label=none value=(height=1 font=swiss '1.0 Unit' '1.2 Unit' '1.4 Unit' '1.6 Unit' ) 
        position=(right bottom  inside) mode=share cborder=black;
axis2 label=('Speed (rpm)');
proc gplot data=burr;
  plot efficiency*(rpm300 rpm400 rpm500) / overlay legend=legend1 haxis=axis1;
  plot efficiency*(spac1 spac12 spac14 spac16) / overlay legend=legend2 haxis=axis2;
run;
quit;
goptions reset=all;

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