Stata The Stata listserver
[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

st: Generating skewed distributions on closed intervals


From   Reza C Daniels <rdaniels@commerce.uct.ac.za>
To   statalist@hsphsun2.harvard.edu
Subject   st: Generating skewed distributions on closed intervals
Date   Thu, 29 Sep 2005 09:25:19 +0200

Dear Statalisters

I have a categorical variable for agegroup in 10 year bands (e.g. 20-30 years old). I would like to convert the categorical age variable to a continuous variable by imposing various distributions on the range of each interval. I then want to conduct sensitivity analysis to my distributional assumptions.

For example: let a = the lower limit and b = upper limit for each age group (e.g. a= 20 years old, b= 30 years old). Keeping the [20,30] example, the four distributions I want to examine are:

1) Uniformly distributed over [20,30].
2) Normally distributed on the closed interval [20,30], with mode at 25.
3) Positively skewed on the closed interval [20,30], with mode at 22.5.
4) Negatively skewed on the closed interval [20,30], with mode at 27.5.

I have tried various commands (including -drawnorm-), but am unable to control my variance to ensure the tails are bounded by [20,30] in the example above (generically, the interval [a,b]).

Any suggestions on the code for all four distributions above would be very much appreciated.

With thanks,
Reza
*
* 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/




© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index