my bad, but that is easily mended:
set obs 1000
gen control_case = cond(_n>500, /*
*/invnorm(uniform())+1.4, /*
*/invnorm(uniform()))
gen status = _n >500
--- "Natarajan, Raj" <[email protected]> wrote:
> Thanks for the suggestion Maarten. The cases have different means as
> you could see from my example.
>
> ________________________________
>
> From: [email protected] on behalf of Maarten Buis
> Sent: Fri 7/13/2007 10:59 AM
> To: [email protected]
> Subject: st: RE: RE: selecting random samples and run a simulation
>
>
>
> As both the controls and the cases are random draws from a normal
> distribution and the two are uncorrelated you can just draw 1000
> random numbers from a normal distribution and call the first 500
> controls and the last 500 cases.
>
> set obs 1000
> gen control_case = invnorm(uniform())
> gen status = _n >500
>
> Hope this helps,
> Maarten
>
> -----------------------------------------
> Maarten L. Buis
> Department of Social Research Methodology
> Vrije Universiteit Amsterdam
> Boelelaan 1081
> 1081 HV Amsterdam
> The Netherlands
>
> visiting address:
> Buitenveldertselaan 3 (Metropolitan), room Z434
>
> +31 20 5986715
>
> http://home.fsw.vu.nl/m.buis/
> -----------------------------------------
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Natarajan,
> Raj
> Sent: vrijdag 13 juli 2007 16:47
> To: [email protected]
> Subject: st: RE: selecting random samples and run a simulation
>
> I sent this e-mail yesterday but did not get any response. So I am
> resending hoiping it will come out.
>
> ________________________________
>
> From: Natarajan, Raj
> Sent: Thu 7/12/2007 8:26 AM
> To: [email protected]
> Subject: selecting random samples and run a simulation
>
>
>
> I would like to draw a random sample of 500 controls and 500 cases
> and calculate the odds ratio; repeat the process for 1000 times.
>
> Example: (draw random sample)
>
> matrix means=(0, 1.4)
>
> matrix stdev = (1, 1)
>
> draw norm control case, n(500) m (means) sds(stdev)
>
>
> the outcome for the first 5 observations will look like this:
>
> control case
>
> -1.315189 .1754738
>
> -.6195259 -.4363556
>
> -1.18018 .2124426
>
> -.2960889 -.5825416
>
> .4534519 -.1245893
>
> PROBLEM: I would like the outcomes for controls and cases to be in
> one column and create a new variable called "status" which is 0 for
> control and 1 for case.
>
> Control_case status
>
> -1.315189 0
>
> -.6195259 0
>
> -1.18018 0
>
> -.2960889 0
>
> .4534519 0
>
> .1754738 1
>
> -.4363556 1
>
> .2124426 1
>
> -.5825416 1
>
> -.1245893 1
>
> I have to run the logistic regression to calculate the odds ratios;
> and repeat the process with different variances.
>
> I would like to know how to make the outcomes arranged in one column
> with the creation of the variables "control_case" and "status".
>
> Thank you for any suggestion.
>
> Raj
>
>
>
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-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands
visiting address:
Buitenveldertselaan 3 (Metropolitan), room Z434
+31 20 5986715
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
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