Dear Statalist,
I am trying to replicate with Stata the two way Between-Within Analysis of
Variance example proposed by Keppel (Design and Analysis, 3rd ed, Table 17-6
pp 375). In this example subjects perform a digit cancellation task and
their performace on this task is measured. The between factor (a) represents
3 different motivations, and the repeated factor (b) represents four trials
on this task. Four subjects were assigned to each of the 3 conditions, and
their performance was measured on 4 trials.
a s b1 b2 b3 b4
a=1 1 2 3 4 13 10 13 4 14 11 19 12 17 15 18 14 20
14 21 15
a=2 5 6 7 8 5 8 14 12 10 15 16 21 17 22 23 26
21 24 23 26
a=3 9 10 11 12 13 9 14 8 24 22 22 18 28 22 28 27
30 24 28 28
After typing :
anova Y A/s|A B A*B, repeated(B)
I get this result :
Number of obs = 48 R-squared =
0.8617
Root MSE = 3.27094 Adj R-squared =
0.7593
Source | Partial SS df MS F Prob >
F
-----------+----------------------------------------------------
Model | 1800.375 20 90.01875 8.41
0.0000
|
A | 414.125 2 207.0625 17.98
0.0007
s|A | 103.625 9 11.5138889
-----------+----------------------------------------------------
B | 1152.41667 3 384.138889 35.90
0.0000
A*B | 130.208333 6 21.7013889 2.03
0.0964
|
Residual | 288.875 27 10.6990741
-----------+----------------------------------------------------
Total | 2089.25 47 44.4521277
However, the ANOVA table reported by is the following :
Source SS df MS
F
A 414.13 2 207.07
6.17
S/A 302.12 9 33.57
B 1,152.42 3
384.14 114.67
A x B 130.20 6 6.48
6.48
B x S/A 90.38 27 3.35
Total 2,089.25 47
Can anyone tell me why I don't obtain the same error terms.
Sincerely yours,
Xavier VIVIAND, M.D.
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