Dear Simon
There was a discussion about degrees of freedom in linear mixed
models on the R-list last week. Have a look at
https://stat.ethz.ch/pipermail/r-help/2006-January/085560.html
and following. There have been earlier discussions about that
topic. Try also:
RSiteSearch("degree freedom mixed")
Regards,
Christoph Buser
--------------------------------------------------------------
Christoph Buser <buser at stat.math.ethz.ch>
Seminar fuer Statistik, LEO C13
ETH (Federal Inst. Technology) 8092 Zurich SWITZERLAND
phone: x-41-44-632-4673 fax: 632-1228
http://stat.ethz.ch/~buser/
--------------------------------------------------------------
Simon Blanchet writes:
> Dear R-users,
>
> I computed a simple mixed models which was:
>
> mod<-lmer(nb ~ site + (1|patelle),tr)
>
> The output was:
>
> Linear mixed-effects model fit by REML
> Formula: nb ~ site + (1 | patelle)
> Data: tr
> AIC BIC logLik MLdeviance REMLdeviance
> 1157.437 1168.686 -574.7184 1164.523 1149.437
> Random effects:
> Groups Name Variance Std.Dev.
> patelle (Intercept) 34.995 5.9157
> Residual 744.736 27.2899
> # of obs: 123, groups: patelle, 33
>
> Fixed effects:
> Estimate Std. Error t value
> (Intercept) 60.3483 4.3929 13.7378
> siteLCN -20.1969 7.8070 -2.5870
> siteLCS -18.2154 6.1514 -2.9612
>
> Correlation of Fixed Effects:
> (Intr) sitLCN
> siteLCN -0.563
> siteLCS -0.714 0.402
>
> I don't understand why D.F. and p-values associated to the
fixed-effects
> coefficients are missing.
> Could anyone help me?
>
> When I tried another model (mod2<-lmer(nb ~ site +
> (1|patelle),tr,family=poisson)), D.F. and p-values were given...
>
> Thank you in advance.
>
> Very sincerely, Simon
>
>
>
> BLANCHET Simon
> PhD student
> Universit?? Laval - Qu??bec-Oc??an / CIRSA
> Pavillon Alexandre-Vachon
> Local 8022
> Qu??bec (Qu??bec), Canada G1K 7P4
> T??l??phone : (418) 656-2131 poste 8022
> courriel : simon.blanchet at giroq.ulaval.ca
>
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