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
visiting address:
Buitenveldertselaan 3 (Metropolitan), room Z434
+31 20 5986715
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
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*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
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* http://www.ats.ucla.edu/stat/stata/
