[R] odds ratio: how to create reference

HI there, i know this is a basic question, though i need some help because this is somewhat away from my current issue, but nevertheless interesting to me... Lets assume i have some estimated probabilities, say estimated by a logit model. i know i can also state them as an odds ratio.

Re: [R] odds ratio: how to create reference

Hi, You can state a probability p as odds p/(1-p) and vice versa. To get an odds ratio you need actually two odds. Then you can get the odds ration of being/having a instead of b by odds(a)/odds(b), where b is the reference level. If you fit a logistic regression model (which means that your

Re: [R] odds ratio: how to create reference

You notice that your reference is for the SAS-procedure glm?! To play around and since you provided no data example I've created some data (by an idea from Frank Harrell jr. http://www.biostat.wustl.edu/archives/html/s-news/2002-04/msg00103.html) n - 30 treat - rep(c('a','b','c'),

Re: [R] odds ratio: how to create reference

Everything Happiness is not perfected until it is shared   -Jane Porter   --- On Tue, 9/23/08, Bunny, lautloscrew.com [EMAIL PROTECTED] wrote: From: Bunny, lautloscrew.com [EMAIL PROTECTED] Subject: [R] odds ratio: how to create

Re: [R] odds ratio: how to create reference

if you did not call levels of an independent variable the outcomes. Many people refer to the dependent variable as the outcome variable. Frank --- On Tue, 9/23/08, Bunny, lautloscrew.com [EMAIL PROTECTED] wrote: From: Bunny, lautloscrew.com [EMAIL PROTECTED] Subject: [R] odds ratio: how