On statistical tests for homogeneity of two bivariate zero-inflated poisson populations

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

3 Scopus Citations
View graph of relations


Related Research Unit(s)


Original languageEnglish
Pages (from-to)44-53
Journal / PublicationJournal of Biopharmaceutical Statistics
Issue number1
Online published20 Jan 2015
Publication statusPublished - 2015


The problem of testing treatment difference in the occurrence of a study endpoint in a randomized parallel-group comparative clinical trial with repeated responses under the assumption that the responses follow a bivariate zero-inflated Poisson (ZIP) distribution is considered. Likelihood ratio test for homogeneity of two bivariate ZIP populations is derived. Approximate formula for sample size calculation is also obtained, which achieves a desired power for detecting a clinically meaningful difference under an alternative hypothesis. An example concerning the comparison of treatment effect in an addictive clinical trial in terms of the number of days of illicit drug use during a month is given for illustrative purposes.

Research Area(s)

  • Erosion counts, Likelihood ratio test, Sample size calculation, Zero-inflated poisson distribution