INTRODUCTION Count data are often collected in chronic disease research, and sometimes these data have a skewed distribution. The number of unhealthy days reported in the Behavioral Risk Factor Surveillance System (BRFSS) is an example of such data: most respondents report zero days. Studies have either categorized the Healthy Days measure or used linear regression models. We used alternative r...

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 ...

Abstract Zero-inflated and hurdle models are widely applied to count data possessing excess zeros, where they can simultaneously model the process from how zeros were generated potentially help mitigate effects of overdispersion relative assumed distribution. Which use depends on generated: zero-inflated add an additional probability mass zero, while two-part comprised a degenerate distribution...

In this paper, we provide a framework for investigation and quantification of impact of object-oriented design choices on the defects in software systems. We report the initial results of an extensive case study, which strongly reinforce earlier, mainly anecdotal, evidence that design aspects related to inheritance and communication between classes can be used as indicators of the most defect-p...

SAS® PROC GLIMMIX fits generalized linear mixed models for nonnormal data with random effects, thus combining features of both PROC GENMOD and PROC MIXED. I will review the ideas behind PROC GLIMMIX and offer examples of Poisson and binary data. PROC NLMIXED also has the capacity to fit these kinds of models. After a brief introduction to that procedure, I will show an example of a zero-inflate...

Counting outcomes such as days of physical activity or servings of fruits and vegetables often have distributions that are highly skewed toward the right with a preponderance of zeros, posing analytical challenges. This paper demonstrates how such outcomes may be analyzed with several modifications to Poisson regression. Five regression models 1) Poisson, 2) overdispersed Poisson, 3) negative b...

background: the number of failed courses and semesters in students are indicatorsof their performance. these amounts have zero inflated (zi) distributions. using zi poisson and negative binomial distributions we can model these count data to find the associated factors and estimate the parameters. this study aims at to investigate the important factors related to the educational performance of ...

We introduce the generalized zero-inflated allocation scheme of placing n labeled balls into N labeled cells. We study the asymptotic behavior of the number of empty cells when (n,N) belongs to the “right” and “left” domain of attraction. An application to the estimation of characteristics of agreement among a set of raters which independently classify subjects into one of two categories is als...