Re: [R] Mixed models and missing p-value...

From: Christoph Buser <buser_at_stat.math.ethz.ch>
Date: Mon 06 Feb 2006 - 19:35:23 EST

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@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
> Université Laval - Québec-Océan / CIRSA
> Pavillon Alexandre-Vachon
> Local 8022
> Québec (Québec), Canada G1K 7P4
> Téléphone : (418) 656-2131 poste 8022
> courriel : simon.blanchet@giroq.ulaval.ca
>
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R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Mon Feb 06 19:45:33 2006

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