The Effects of Dispersion Parameters and Test for Equality of Dispersion Parameters in Zero-Truncated Bivariate Generalized Poisson Models

제로절단된 이변량 일반화 포아송 분포에서 산포모수의 효과 및 산포의 동일성에 대한 검정

  • Received : 20100200
  • Accepted : 20100300
  • Published : 2010.06.30


This study, investigates the effects of dispersion parameters between two response variables in zero-truncated bivariate generalized Poisson distributions. A Monte Carlo study shows that the zero-truncated bivariate Poisson and negative binomial models fit poorly wherein the zero-truncated bivariate count data has heterogeneous dispersion parameters on dependent variables. In addition, we derive the score test for testing the equality of the dispersion parameters and compare its efficiency with the likelihood ratio test.


Bivariate generalized Poisson distribution;bivariate negative binomial distribution;likelihood ratio test;score test;zero-truncation


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Supported by : 한국학술진흥재단