st: Mixed question

[Morten Hesse <mh@crf.au.dk>]

Hi,
My question is probably more a general statistical question than a Stata 
question (and maybe one for beginners). But I wonder: how do I estimate 
the significance of random effects in multilevel models, such as 
xtmixed? I suspect there is a reason why neither GLLAMM nor xtmixed 
gives significance levels and standardized effect sizes, but just 
coefficients and standard errors. Of course, I could calculate a Z 
statistic from these, but since the program doesn't I assume that is wrong.
Am I right?
Greetings
Morten Hesse
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