Re: AW: st: AW: Using svy with by

[Nick Cox <n.j.cox@stata.com>]

_gwtmean is a package from SSC by David Kantor. It is documented briefly 
(and sufficiently) in the package description

. ssc desc _gwtmean

and at greater length within the code

. ssc type _gwtmean.ado

Incidentally, Martin's code

. by f: gen mean=mean(pr)

contains a typo. Use -egen-, not -gen-.

Nick

Martin Weiss wrote:

> Is this thing documented anywhere? Does not seem to supply a help file...

> [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Austin Nichols
>
> ssc install _gwtmean
> sysuse auto
> egen m=wtmean(price), by(rep78) weight(weight)
>
> On Tue, Aug 4, 2009 at 7:16 AM, Martin Weiss<martin.weiss1@gmx.de> wrote:
> > <>
> >
> > Apart from other problems, you are treating -mean- as if it was a
> function.
> > You have to -generate- the mean estimate first, and then do the -replace-
> > separately...
> >
> > Note the difference:
> >
> > *************
> > sysuse auto, clear
> > by f: gen mean=mean(pr)
> > *************
> >
> > *************
> > sysuse auto, clear
> > gen meanpr=.
> > levelsof for, loc(myfor)
> >
> > foreach lev in `myfor'{
> >        su pr if for==`lev', mean
> >        replace meanpr=`r(mean)' if for==`lev'
> > }
> > *************

A.Dijkstra@lse.ac.uk

> > I'm trying to find a way around a problem. The code below results in an
> > error since svy cannot by combined with by. I cannot think of another way
> to
> > get the equivalent result I need, however, since the mean I'm attempting
> to
> > calculate must be run using svy.
> >
> > Any ideas?
> >
> > Code:
> >
> > foreach varname of varlist `PAYMENTVARS' {
> > generate `varname'PANAVG = 0
> >  by DUPERSID PURCHRD, sort: svy: replace `varname'PANAVG = mean(`varname')
> >  by DUPERSID PURCHRD: keep if _n==_N
> >  drop `varname'
> >  }
> >
> >
> > Error:
> >
> > svy may not be combined with by
> > r(190);

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