[R-sig-ME] weights-option in lmer

Ben Pelzer b.pelzer at maw.ru.nl
Wed May 26 21:26:53 CEST 2010

Dear all,

I have to related questions concerning the weights-option in lmer.

1) Imagine a two level design, like respondents in a number of 
countries. From each country one has a sample and the percentages of 
males and females in each country differ from the population percentages 
for that country. Can one use the weights-option in lmer to obtain a 
weighted sample for which the (weighted) male/female sample-percentages 
are equal to the population percentages, to achieve more representative 

2) If one has aggregated data-records, each record containing the values 
of the dependent and independent variables and also the number of 
lower-level cases in a variable named 'nofcases', can the ' 
weight=nofcases'  option in lmer then be used to 'disaggregate' the 
data? And are the resulting standard errors then correct, i.e. related 
to the total number of lower-level (disaggregated) cases?

If the answer to these question is 'yes', which I hope, does that also 
hold for the nonlinear, especially the binomial family models?  

Thanks for any help!!


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