[R-sig-ME] How to “weight” measurements (family means)?

[demont at access.uzh.ch]

Dear all,

I have recently started working with the lme4 package and its lmer function. 
My data file is based on family means. I do not have the row data for the 
individuals but I do know for every family on how many individuals the 
family means are based (i.e. how many individuals per family I have 
measured).
How can I fit a mixed-effects model to this data with lmer so that my family 
means are weighted with an appropriate weighting factor (i.e. weights my 
family means according to the number of offspring per family measured for 
this family = more weight for family means that are based upon many 
individuals, because I have more confidence in this measurements)?? Does 
this involve using the optional vector “weights”??
Despite going through the reference manual, the vignettes and the 
R-sig-mixed-models archives I did not find a clear answer to this very 
fundamental problem and would hence be deeply grateful for a specific and 
detailed answer!

Sincerely,
Marco





**************************************************************
Marco Demont
Zoological Museum
University of Zuerich
Winterthurerstrasse 190
CH-8057 Zuerich
Switzerland

Tel.: +41 44 635 47 79
demont at access.uzh.ch
demont at gmx.ch
www.unizh.ch/zoolmus/zmneu/englisch/forschung_e/demont_marco_e.html