Re: st: sd() does not work with forvalues

[Nick Cox <njcoxstata@gmail.com>]

Richard is correct. The error is that -sd()- is an -egen- function and  
as such can only be used in
-egen- calls.

Nick

On 15 Jul 2011, at 18:31, Richard Goldstein <richgold@ix.netcom.com>  
wrote:
> my guess is that the error message refers to the line that starts "gen
> nosddff`i'" rather than to the egen line -- and that line shouldn't  
> work
> outside the loop either; however, you have already calculated this  
> value
> and saved it in a variable so why not use that variable at that point?
> i.e., change the line to
>
> gen nosddff`i'=diffmedi`i'/sddf`i'
>
> Rich
>
> On 7/15/11 1:20 PM, Wilhelm Kluemper wrote:
> > Hello STATA community,
> >
> > I am trying out a code where I want to create the standard deviation
> > of a var as a new var with a loop:
> >
> > dfbeta
> >
> > forvalues i = 3/85 {
> > egen df`i'med = median(_dfbeta_`i')
> > egen sddf`i'= sd(_dfbeta_`i')
> > gen diffmedi`i'=_dfbeta_`i'-df`i'med
> > gen absdiffmedi`i' = abs(diffmedi`i')
> > gen nosddff`i'= diffmedi`i'/sd(_dfbeta_`i')
> > drop if nosddff`i'>=2
> > }
> >
> > I keep getting this message:
> >
> > unknown function sd()
> >
> > It works perfectly without the forvalues loop but not within. Does
> > anybody have a clue why that is and what I could do about it?
> >
> > Thanks already
> >
> > Wilhelm
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