# Re: st: RE: how to constrain rowtotal?

 From Maarten buis <[email protected]> To [email protected] Subject Re: st: RE: how to constrain rowtotal? Date Sun, 27 Jan 2008 19:41:35 +0000 (GMT)

```Even better would be:
gen unif = uniform()
gen which = cond(unif < 0.721, "A",        ///
cond(unif < 0.923, "B",        ///
cond(unif < 0.990, "C", "D")))
-- Maarten

--- Nick Cox <[email protected]> wrote:

> This may help:
>
> . gen which = cond(uniform() < 0.721, "A",
>               cond(uniform() < 0.923, "B",
> 		  cond(uniform() < 0.990, "C", "D")))
>
> Also see
>
> SJ-7-3  pr0032  Stata tip 48: Discrete uses for uniform()
> M. L. Buis
> Q3/07   SJ 7(3):434--435
>         tip on using uniform() to create random draws from a
>         discrete distribution where each possible value has a
>         known probability
>
> Nick
> [email protected]
>
> Carlo Lazzaro
>
> In a Markov Model I have four variables (A= 0.721; B= 0.202; C=
> 0.067;
> D=
> 0.010) showing transition probabilities from/to different health
> states,
> which are both exhaustive and mutual exclusive (that is: Prob_A+
> Prob_B+
> Prob_C+ Prob_D=1)
>
> I would like to randomly resampling the base case value of each
> variable
> (let's say using -uniform()-): how can I constrain egen Resampling=
> rowtotal
> (A_uniform B_uniform C_uniform D_uniform) =1 after each random
> resample?
>
>
> *
> *   For searches and help try:
> *   http://www.stata.com/support/faqs/res/findit.html
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/
>

-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands

Buitenveldertselaan 3 (Metropolitan), room Z434

+31 20 5986715

http://home.fsw.vu.nl/m.buis/
-----------------------------------------

__________________________________________________________
Sent from Yahoo! Mail - a smarter inbox http://uk.mail.yahoo.com

*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/
```