[R] library(car): Anova and repeated measures without between subjects factors
Ralf Goertz
R_Goertz at web.de
Tue Oct 16 17:20:07 CEST 2007
Hi,
sorry if this is explained somewhere but I didn't find anything.
How can I use "Anova" from the car package to test a modell without
between subject's factors? Suppose I have the following data
mat.1 mat.2 mat.3 di ex
1 85 85 88 1 1
2 90 92 93 1 1
3 97 97 94 1 1
4 80 82 83 1 1
5 91 92 91 1 1
6 83 83 84 2 1
7 87 88 90 2 1
8 92 94 95 2 1
9 97 99 96 2 1
10 100 97 100 2 1
11 86 86 84 1 2
12 93 103 104 1 2
13 90 92 93 1 2
14 95 96 100 1 2
15 89 96 95 1 2
16 84 86 89 2 2
17 103 109 90 2 2
18 92 96 101 2 2
19 97 98 100 2 2
20 102 104 103 2 2
21 93 98 110 1 3
22 98 104 112 1 3
23 98 105 99 1 3
24 87 132 120 1 3
25 94 110 116 1 3
26 95 126 143 2 3
27 100 126 140 2 3
28 103 124 140 2 3
29 94 135 130 2 3
30 99 111 150 2 3
Using
> Anova(lm(mat~di*ex,data=data),idata=data.frame(zeit=ordered(1:3)),idesign=~zeit)
Type II Repeated Measures MANOVA Tests: Pillai test statistic
Df test stat approx F num Df den Df Pr(>F)
di 1 0.377 14.524 1 24 0.0008483 ***
ex 2 0.800 47.915 2 24 4.166e-09 ***
di:ex 2 0.281 4.695 2 24 0.0190230 *
zeit 1 0.782 41.209 2 23 2.491e-08 ***
di:zeit 1 0.252 3.865 2 23 0.0357258 *
ex:zeit 2 0.836 8.611 4 48 2.538e-05 ***
di:ex:zeit 2 0.518 4.189 4 48 0.0054586 **
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
works as expected. But every once in a while I have a model without
between subject's factors. So I thought of
> Anova(lm(mat~1,data=data),idata=data.frame(zeit=factor(1:3)),idesign=~zeit)
Fehler in L %*% B : nicht passende Argumente
(Error in L %*% B : non matching arguments)
On the other hand using anova.mlm I get
> anova.mlm(lm(mat~1,data),idata=data.frame(zeit=factor(1:3)),X=~1,test="Spherical")
Analysis of Variance Table
Contrasts orthogonal to
~1
Greenhouse-Geisser epsilon: 0.7464
Huynh-Feldt epsilon: 0.7777
Df F num Df den Df Pr(>F) G-G Pr H-F Pr
(Intercept) 1 11.767 2 58 5.1375e-05 3.1183e-04 2.4939e-04
Residuals 29
How can achieve this with Anova?
Thanks in advance,
Ralf
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