Re: [R] changing degrees of freedom in summary.lm()

From: Spencer Graves <spencer.graves_at_pdf.com>
Date: Tue 28 Feb 2006 - 03:59:09 EST

          I believe your difficulties will be greatly enlightened by using either lme in library(nlme) or lmer associated with the lme4 package. Essential documentation is Pinheiro and Bates (2000) Mixed-Effects Models in S and S-Plus (Springer).

	  hope this helps.
	  spencer graves

Joseph LeBouton wrote:
> Hello all,
>
> I'm trying to do a nested linear model with a dataset that incorporates
> an observation for each of several classes within each of several plots.
> I have 219 plots, and 17 classes within each plot.
>
> data.frame has columns "plot","class","age","dep.var"
>
> With lm(dep.var~class*age),
>
> The summary(lm) function returns t-test and F-test values evaluated as
> though I were working with 219*17-17=3706 degrees of freedom, when in
> fact I have but 219-17=202 df. I'm probably being dense on this one,
> but is there a way I can set df to the proper number so that summary.lm
> does the correct significance test? Or should I be doing an entirely
> different anlaysis?
>
> Thanks,
>
> -jlb



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 Tue Feb 28 04:06:48 2006

This archive was generated by hypermail 2.1.8 : Tue 28 Feb 2006 - 06:08:49 EST