The zeroth lesson is how to find this out for 
yourself. The manual entry [R] summarize 
and on-line help for -summarize- certainly 
explain this. It is a bit trickier to find out 
what it does by trying it out, as it leaves 
no output in the Results window, but only 
a set of results that may be seen by typing -return 
list-. But that's explained in the sources
mentioned. 
Nick 
[email protected] 
Melissa D. A. Carlson
> 
> Thanks so much for this reply. Just a quick follow-up question:
> What does "sum year, mean" do?
> 
Stas Kolenikov
 
> an easy thing to do is to create use the variable -year-, or better
> centered version of that,
> 
> sum year, mean
> g cyear = year - r(mean)
> 
> and put it into your regression
> 
> svyreg male cyear
> 
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