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st: xtmixed question


From   David Airey <david.airey@Vanderbilt.Edu>
To   statalist@hsphsun2.harvard.edu
Subject   st: xtmixed question
Date   Fri, 18 May 2007 15:38:03 -0500

When I use a maximum likelihood mixed model with clusters that have unequal sizes, are the fixed effects modeled in a way that reflects this?

So in a model like,

xtmixed y treatment || group:

where multiple groups are each assigned to one of two treatments, but groups are different sizes, is this accounted for by these types of models?

So if I were to average the groups and use the summary statistics in a linear regression model, I might weight the analysis by cluster size, reducing influence of small clusters relative to large clusters. If I use xtmixed directly, should I worry about this?
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