[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

st: simulated data for logistic regression... remedial algebra help?

From   "Daniel Waxman" <>
To   <>
Subject   st: simulated data for logistic regression... remedial algebra help?
Date   Sat, 17 Nov 2007 18:44:26 -0500

I am trying to create a series of simulated data sets for use in logistic
regression with the following properties:

Mortality (outcome) remains constant.   There is a single dichotomous
independent variable whose odds ratio (coefficient) and proportion of
positives can vary between the sets.  It all comes down to solving for the
intercept (`b0'), given the following relationships:


Sad to admit, but I am bumping up against the limitations of my algebra
I'd imagine this is trivial for many of you...



set obs 1000
local odds=2
local proportion_positive= .10
local mortality = .05

gen test=uniform()<`proportion_positive’


************solve for `b0' here************


gen probability_negative=invlogit(`b0’)
gen probability_positive=invlogit(log(`odds’)+`b0’)

gen died=uniform() < cond(test==0,probability_negative,probability_positive)

logistic died test




No virus found in this outgoing message.
Checked by AVG Free Edition. 
Version: 7.5.503 / Virus Database: 269.16.0/1136 - Release Date: 11/17/2007
2:55 PM

*   For searches and help try:

© Copyright 1996–2015 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index