Dear Elizabeth, When I looked for this a couple of years ago, I found DF's to be discussed in the book by Pinheiro & Bates "Mixed effects models for S and S-Plus", as well as the documentation for SAS's PROC MIXED (I believe that the discussion on df's on the SAS "manual" was more complete than on the "SAS system for mixed models book" ---and I think html versions of the manuals for v 8 of SAS can be found on the web). I do not remember specifically, though, whether this discussions mentioned explicitly DFs for fixed effects with crossed random effects (I do not have the references here now).
Best, R. On Wednesday 08 September 2004 19:54, Elizabeth Lynch wrote: > Hi, > > I'm looking for pointers/references on calculating den DF's for fixed > effects when using crossed random effects. Also, is there an implementation > of simulate.lme that I could use in lme4? > > Thanks, > > Elizabeth Lynch > > Douglas Bates wrote: > >Alexandre Galvão Patriota wrote: > >>Hi, I'm having some problems regarding the packages > >>lme4 and nlme, more specifically in the denominator > >>degrees of freedom. <SNIP> > > > >The lme4 package is under development and only has a stub for the code > > that calculates the denominator degrees of freedom. > > > >These Wald-type tests using the F and t distributions are approximations > > at best. In that sense there is no "correct" degrees of freedom. I > > think the more accurate tests may end up being the restricted likelihood > > ratio tests that Greg Reinsel and his student Mr. Ahn were working on at > > the time of Greg's death. > > > >______________________________________________ > >[EMAIL PROTECTED] mailing list > >https://stat.ethz.ch/mailman/listinfo/r-help > >PLEASE do read the posting guide! > >http://www.R-project.org/posting-guide.html > > hthttp://messenger.msn.click-url.com/go/onm00200471ave/direct/01/ > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html -- Ramón Díaz-Uriarte Bioinformatics Unit Centro Nacional de Investigaciones Oncológicas (CNIO) (Spanish National Cancer Center) Melchor Fernández Almagro, 3 28029 Madrid (Spain) Fax: +-34-91-224-6972 Phone: +-34-91-224-6900 http://ligarto.org/rdiaz PGP KeyID: 0xE89B3462 (http://ligarto.org/rdiaz/0xE89B3462.asc) ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html