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  • Testing for varying zero-in...
    Xie, Feng-Chang; Lin, Jin-Guan; Wei, Bo-Cheng

    Journal of applied statistics, 09/2010, Volume: 37, Issue: 9
    Journal Article

    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.