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Re: Re: st: use random values in a calculation


From   "Samuel R. Lucas" <lucaselastic@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: Re: st: use random values in a calculation
Date   Mon, 4 Jul 2011 09:04:35 -0700

Does this mean you need an opt5 that equals zero?  All I can see is
opt1-opt4 that equal .05, .1, .15, and .2

Not sure this solves your ultimate problem, but it can't hurt.

Take care.
Sam

On Mon, Jul 4, 2011 at 7:52 AM, Zhi Su <su.zh@husky.neu.edu> wrote:
> Hi ,Eric,
>
>  The ratio to multiply one of the variables could be 0 too. Probably
> I do not ask the question right. The variables v1, v2, v3, v4 are
> known. The ratios multiply them are chosen from (0,0.05,0.1,0.15,0.2).
> Then each variable multiplied by a ratio are sum up. Totally, there
> are 5*5*5*5=625 combination for these four variables multipled by a
> ratio. Then I generate 625 variables for 625 types of sum.
>
>  Thank you!
>
> Date: Sat, 2 Jul 2011 04:48:49 +0000
> From: Eric Booth <ebooth@ppri.tamu.edu>
> Subject: Re: st: use random values in a calculation
>
> <>
>
> Here's one approach:
>
> ************************
> clear
> set obs 625
> g n = _n
> tostring n, replace
> g str4 var = "s" + n
>
> **create fake v1-v4 variables for example:
> forv nn = 1/4 {
>    g v`nn' = runiform()*10
>    }
>
> **create random opt1-opt4 to multiply by v1-v4:
> forv n = 1/4 {
>    g opt`n' = int(runiform()*5)
>    replace opt`n' = .05 if opt`n'==1
>    replace opt`n' = .1 if opt`n'==2
>    replace opt`n' = .15 if opt`n'==3
>    replace opt`n' = .2 if opt`n'==4
>    }
>
> **create sum of all v*opt vars:
> g s = (v1*opt1)+(v2*opt2)+(v3*opt3)+(v4*opt4)
> order var s
> l  in 1/9
> **
> keep var s
>
> **use -sxpose- to create s1-s625 variables:
>        **-sxpose- is from SSC**
>        cap which sxpose
>        if _rc ssc install sxpose, replace
> sxpose , clear firstnames force destring
> ************************
>
> - - Eric
> __
> Eric A. Booth
> Public Policy Research Institute
> Texas A&M University
> ebooth@ppri.tamu.edu
>
>
>
> On Jul 1, 2011, at 9:46 PM, Zhi Su wrote:
>
>> Dear Statalists,
>>
>>  I need to generate a set of variables that are som of four variables
>> v1 v2 v3 v4 multipled by a ratio r1 r2 r3 r4 which are randomly chosen
>> from (0, 0.05,0.1,0.15,0.2). For example,
>> s0=v1*0+v2*0+v3*0+v4*0
>> s1=v1*0.05+v2*0+v3*0_v4*0
>> s2=v1*0.05+v2*0.05+v3*0+v4*0
>> .
>> .
>> .
>> s625=v1*0.2+v2*0.2+v3*0.2+v4*0.2
>>
>> How can I use commands to generate these 625 variables?
>>
>> Thank you!
>>
>
> --
> Zhi Su
> 348 Holmes Hall
> Northeastern University
> 360 Huntington Avenue
> Boston, MA 02115
> Office:1-617-373-2316
> email:su.zh@husky.neu.edu
> *
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>

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