[R] Anohter anova.mlm problem

From: Bela Bauer <bela_b_at_gmx.net>
Date: Wed 15 Jun 2005 - 17:59:41 EST


Hi,

yet another anova.mlm problem - it doesn't seem to end. This time, I have a setup with a few within-subject factors and a between-subject factor (SGROUP). Consider the most simple case with only one within-factor (apo):

> mlmfit0 <- lm(data.n ~ 0 + SGROUP)
> mlmfit1 <- lm(data.n ~ 1 + SGROUP)
> anova(mlmfit1,mlmfit0,test="Spherical",M=~hemi,X=~1)
Analysis of Variance Table

Model 1: data.n ~ 1 + SGROUP
Model 2: data.n ~ 0 + SGROUP

Contrasts orthogonal to
~1

Contrasts spanned by
~hemi

Greenhouse-Geisser epsilon: 0.6829
Huynh-Feldt epsilon: 0.7127

  Res.Df Df Gen.var. F num Df den Df Pr(>F) G-G Pr H-F Pr

1     22     0.54295
2     22  0  0.54295 Inf      0     44

Warning messages:
1: NaNs produced in: pf(q, df1, df2, lower.tail, log.p)
2: NaNs produced in: pf(q, df1, df2, lower.tail, log.p)
3: NaNs produced in: pf(q, df1, df2, lower.tail, log.p)


Now, those G-G and H-F epsilons it gives me are correct (at least G-G, the H-F seems to be affected by the R vs SAS difference in the calculation). But whatever happened to everything else?
I've played around with the source in mlm.R, and it looks to be as though the problem is related to this:
https://stat.ethz.ch/pipermail/r-devel/2005-April/032925.html

Is there a solution to this problem? Am I doing something wrong? The data looks like this:

> hemi

 [1] 1 1 1 1 1 1 2 2 2 2 2 2 3 3 3 3 3 3 Levels: 1 2 3
> SGROUP

 [1] 2 2 2 2 2 2 1 1 1 1 2 2 2 1 1 1 2 1 1 1 2 1 2 1 Levels: 1 2
> dim(data.n)

[1] 24 18

It works fine with the univariate analysis (aov())...

Thanks again,

Bela

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Received on Wed Jun 15 18:03:14 2005

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