topic Re: poisson and negative binomial distribution in SAS Programming

poisson and negative binomial distribution

Unay13 — Thu, 29 Mar 2018 22:08:56 GMT

Hello,

I need to perform a Negative Binomial and Poisson distribution for a data that I have. Using GENMOD, COUNTREG and specifying distribution as NB or Poisson, I got the mean as a linear function of x Variables. However, I have my own defined Non linear function such as Hoerl and Sigmoidal function that I need to incorporate in the distribution.

For example, instead of this form.

The function I need to use is below moreover the bottom 2. Where miu can is in terms of E.

Any help would be greatly appreciated.

Re: poisson and negative binomial distribution

PGStats — Thu, 29 Mar 2018 22:40:55 GMT

Your equations don't show up. Anyway, you should consider using proc nlmixed.

Re: poisson and negative binomial distribution

Unay13 — Thu, 29 Mar 2018 23:55:36 GMT

The equations are the Sigmoidal and Hoerl Function. As I am new to SAS I did not exactly understand how proc nlmixed works. Could you please help me with that?

Re: poisson and negative binomial distribution

PGStats — Fri, 30 Mar 2018 03:33:44 GMT

I'm not a real user of proc nlmixed , I just went with its description. The negbin distribution is often difficult to fit with proc countreg or proc glimmix, so I would expect at least the same level of difficulty with proc nlmixed. You might ask for help about nlmixed on the SAS Statistical Procedures Community to find some expertise. Best of luck.