We consider two classes of exponential dispersion models discrete probability distributions which are defined by specifying their variance functions in mean value parameterization. These were considered our earlier paper as overdispersed zero-inflated distributions. In this we analyze the application these to fit count data having and statistics. For reason, first elaborate on computational asp...

We introduce three new commands—nop, ziop2, and ziop3—for the estimation of a three-part nested ordered probit model, two-part zero-inflated models Harris Zhao (2007, Journal Econometrics 141: 1073–1099) Brooks, Harris, Spencer (2012, Economics Letters 117: 683–686), model Sirchenko (2020, Studies in Nonlinear Dynamics 24: 1) for ordinal outcomes, with both exogenous endogenous switching. The a...

Many applications involve count data from a process that yields an excess number of zeros. Zero-inflated count models, in particular, zero-inflated Poisson (ZIP) and zero-inflated negative binomial (ZINB) models, along with Poisson hurdle models, are commonly used to address this problem. However, these models struggle to explain extreme incidence of zeros (say more than 80%), especially to fin...

In this paper we have considered several regression models to fit the count data that encounter in the field of Biometrical, Environmental, Social Sciences and Transportation Engineering. We have fitted Poisson (PO), Negative Binomial (NB), Zero-Inflated Poisson (ZIP) and Zero-Inflated Negative Binomial (ZINB) regression models to run-off-road (ROR) crash data which collected on arterial roads ...

This study attempts to explore the viability of dual-state models (i.e., zero-inflated and hurdle models) for traffic analysis zones (TAZs) based pedestrian and bicycle crash frequency analysis. Additionally, spatial spillover effects are explored in the models by employing exogenous variables from neighboring zones. The dual-state models such as zero-inflated negative binomial and hurdle negat...