On May 13, 2013, at 9:08 AM, Anamika Chaudhuri wrote: > Hi David: > > My main goal is to be able to find the method/model that estimates the random > effect of site on multiple binomial outcomes in multicenter clinical trial > settings. The methods you have suggested are fixed effects models, right?
We apparently have a completely different understanding of mixed effects modeling terminology. Please read the Posting Guide.And as I said before . this is not the correct venue for that discussion, which was why I responded to the more statistical part of the question on CrossValidated. (If you want to pursue this in an R venue, then you would better advised to post your follow-up question on the R-SIG-Mixed-models mailing list.) http://www.r-project.org/mail.html -- David. > > Thanks > Anamika > > On Sun, May 12, 2013 at 9:44 PM, David Winsemius <dwinsem...@comcast.net> > wrote: > > 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 Agrestis > 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 > > David Winsemius Alameda, CA, USA [[alternative HTML version deleted]]
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