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RE: st: RE: using loop to generate distributions with different means and standard deviations


From   "Sarah Edgington" <sedging@ucla.edu>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: RE: using loop to generate distributions with different means and standard deviations
Date   Wed, 18 May 2011 10:51:56 -0700

Lance,
That's a different problem.  From your original post I assumed you had all
the variables already created.
One strategy for writing loops is to write out the code for the first two
examples of something repetitive you want to do.  Then identify the parts of
the example that remain the same across the examples.
If you post the code your trying to repeat we may be able to help you but
your current description is too vague for me to do much more than offer
vague suggestions of how to think about loops.
-Sarah

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Lance Wiggains
Sent: Wednesday, May 18, 2011 10:36 AM
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: RE: using loop to generate distributions with different
means and standard deviations

I've tried that but the problem is that I'm pre-calculating the means and
sd's for the variable because I'm only using the last 3-4 observations for
each variable to calculate those values. I'm doing this because I want it to
reflect the changes that happen recently. My mean function uses tssmooth,
with weights (1 1<2>), to average the last 3 weeks of sales. So if sales
were 70,80,90, and 100 I get a value of 92.5 for my mean. It also calculates
a SD for the last 3-4 observations. Then I want to plug those numbers into
the drawnorm function using a loop. Any idea about how that would work?

Lance

On Wed, May 18, 2011 at 1:16 PM, Sarah Edgington <sedging@ucla.edu> wrote:
> Lance,
> Try something like this:
>
>        forv i=1/3 {
>                 drawnorm name`i', m(mean_var`i') sd(sd_var`i')
>        }
>
> You'll run into problems, though, if your data actually includes the 
> variable names you list since there isn't a sd_var1.
>
> -Sarah
>
> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Lance 
> Wiggains
> Sent: Wednesday, May 18, 2011 10:09 AM
> To: statalist@hsphsun2.harvard.edu
> Subject: st: using loop to generate distributions with different means 
> and standard deviations
>
> Statalist members,
>
> I'm trying to get Stata to generate a distribution of data from 
> variables in my data set.
>
> My appended data looks like this
> mean_var1=90
> standard_deviation_var1=5
> mean_var2=100
> sd_var2=10
> mean var3=110
> sd_var3=15
> and so on
>
> I'm need a loop that will take my variables and create the 
> distributions for me.
> I've been using the drawnorm command
>     drawnorm name1, m(mean_var1) sd(sd_var1) but I can't get it to 
> recognize more than 1 variable at a time
>
> I want it to perform the distribution command for each pair of my
variables.
> I.e. (m_var1, sd_var1), (m_var2, sd_var2) , (m_var3, sd_var3)
>
> Thanks for your consideration,
>
> Lance
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