st: problems with ztnb and ztp

[Gillian Holloway <ghollowa@ualberta.ca>]

Hi Statalisters,

I'm analyzing zero-truncated bird count data using the standard code for 
zero-truncated poisson and zero-truncated negative binomial regression.  
However, when I calculate the predicted values I'm getting some 
estimates below 1, even though 1 is the minimum observed value in the 
data. Any ideas what the problem could be?

Example code:

ztp Count SLSoft if Count>0 & Sppcode==38, iterate(100)
predict GRJA


Thanks, Gillian
****************

Alberta Biodiversity Monitoring Institute
Department of Biological Sciences
CW 405, Biological Sciences Centre
University of Alberta


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