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Re: st: Creating a data subset with subjects chosen at random


From   brendan.halpin@ul.ie (Brendan Halpin)
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Creating a data subset with subjects chosen at random
Date   Fri, 15 Jun 2012 16:08:39 +0100

On Fri, Jun 15 2012, Amal Khanolkar wrote:

> Just a question: 
>
> in the command line: by cbirth: 
>
> gen subsamp = _n <= (_N+0.5)*0.05
>
> 0.05 specifies 5% proportion right?

Yes. If you replace this by 100000/2991200.0 you should get close to
exactly 100,000 cases. 

I think I'm correct in adding 0.5 to _N for rounding purposes; I haven't
tested it, and with this sample size it is likely immaterial.

Regards,

Brendan
-- 
Brendan Halpin,   Department of Sociology,   University of Limerick,   Ireland
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