Tom,
Try this reference:
Welsh, A. H., R. B. Cunningham, C. F. Donnelly and D. B. Lindenmayer. 1996.
Modelling the abundance of rare species - statistical models for counts with
extra zeros. Ecological Modelling 88(1-3): 297-308.
Good luck!
Andrew
On 12/18/00 2:20 AM, "Richards, Tom" <richards@pci.upmc.edu> wrote:
> Hello:
>
> I want to fit a model to count data where many counts are zero. I would
> like to posit that the baseline value of an immunologic marker impacts
> whether or not a patient experiences any events at all, and the conditional
> (on being > 0) expectation of the remaining counts as a function of the
> percent inhibition of the immunologic marker. I guess I want to use a
> logistic model for the probability of experiencing any events, and a Poisson
> model for the conditional expectation. This sounds like it should be a
> familiar problem. Can someone point me in the right direction? Thanks in
> advance for any help.
>
> Tom Richards
> ---------------------------------------------------------------------
> This message was distributed by s-news@lists.biostat.wustl.edu. To
> unsubscribe send e-mail to s-news-request@lists.biostat.wustl.edu with
> the BODY of the message: unsubscribe s-news
>
|