[R] degrees of freedom (lme4 and nlme)

Elizabeth Lynch elynchabeth at hotmail.com
Wed Sep 8 19:54:47 CEST 2004


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?


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.
>R-help at stat.math.ethz.ch mailing list
>PLEASE do read the posting guide! 

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