Testing for varying zero-inflation and dispersion in generalized Poisson regression models |
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| Authors: | Feng-Chang Xie Jin-Guan Lin Bo-Cheng Wei |
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| Institution: | 1. Department of Applied Mathematics , Nanjing Agricultural University , Nanjing , 210095 , People's Republic of China;2. Department of Mathematics , Southeast University , Nanjing , 210096 , People's Republic of China;3. Department of Mathematics , Southeast University , Nanjing , 210096 , People's Republic of China |
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| Abstract: | Homogeneity of dispersion parameters and zero-inflation parameters is a standard assumption in zero-inflated generalized Poisson regression (ZIGPR) models. However, this assumption may be not appropriate in some situations. This work develops a score test for varying dispersion and/or zero-inflation parameter in the ZIGPR models, and corresponding test statistics are obtained. Two numerical examples are given to illustrate our methodology, and the properties of score test statistics are investigated through Monte Carlo simulations. |
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| Keywords: | generalized Poisson regression models zero-inflation dispersion score test test of homogeneity simulation study |
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