[R] Multinomial-Dirichlet using R
David Winsemius
dwinsemius at comcast.net
Mon May 13 03:44:02 CEST 2013
On May 12, 2013, at 4:44 PM, Anamika Chaudhuri wrote:
> Hi:
>
> I have asked this question on Cross-Validated. So it might be a cross
> posting but havent received any responses to it.
>
> I am trying to see which distribution will best fit the data I am working
> on. The dataset is as following:
>
> Site Nausea headache Abdominal Distension
> 1 17 5 10
> 2 12 8 7
> .....
>
> So each site has total # adverse events for each type/category and have
> equal # patients per site, say 60 and there are 63 sites. If I were to
> analyze the data for multiple outcomes per site, the number of events per
> category given the category response rates can be assumed to be
> independently distributed. They can be modeled by a multinomial
> distribution with parameters n=60 and category response rates pi1, . . . ,
> piC for site i. The individual variation in category response rates can be
> modeled by a Dirichlet distribution.
>
> Just wondering if I am thinking through this correctly.
> If so, could someone share some thoughts on how this could be done in R?
This is more of a statistical question, and I'm surprised no advice was offered on CrossValidated. I responded there. You should find that this sort of question is handled in "S-PLUS (and R) Manual to Accompany Agresti’s Categorical Data Analysis" (2002) 2nd edition by Laura A. Thompson, 2006©, which is very easy to find with a Google search.
--
David Winsemius
Alameda, CA, USA
More information about the R-help
mailing list