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Document type:
Zeitschriftenaufsatz 
Author(s):
Min, A., and Czado, C. 
Title:
Testing for zero-modification in count regression models. 
Abstract:
Count data often exhibit overdispersion and/or require an adjustment for zero outcomes with respect to a Poisson model. Zero-modified Poisson (ZMP) and zeromodified generalized Poisson (ZMGP) regression models are useful classes of models for such data. In the literature so far only score tests are used for testing the necessity of this adjustment. We address this problem by using Wald and likelihood ratio tests. We show how poor the performance of the score tests can be in comparison...    »
 
Keywords:
generalized Poisson distribution; likelihood ratio test; maximum likelihood estimate; overdispersion; score test; Wald test; zero-inflation, zero-modification 
Journal title:
Statistica Sinica 
Year:
2010 
Journal volume:
20 
Pages contribution:
323-341 
Reviewed:
ja 
Language:
en 
Status:
Verlagsversion / published 
Semester:
SS 10 
Format:
Text