Bo-Cheng Wei

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For clustered count data with excess zeros where the observations are either over-dispersed or under-dispersed, the zero-inflated generalized Poisson mixed (ZIGPM) regression model may be appropriate, in which the baseline discrete distribution is a generalized Poisson distribution, which is a natural extension of standard Poisson distribution. Motivated by(More)
In regression diagnostics, the case deletion model (CDM) and the mean shift outlier model (MSOM) are commonly used in practice. In this paper we show that the estimates of CDM and MSOM are equal in a wide class of statistical models, which include LSE, MLE, Bayesian estimate and M-estimate in linear and nonlinear regression models; MLE in generalized linear(More)
This work develops diagnostics for skew-t-normal nonlinear models which provides an useful extension for ordinary normal regression models when the data set under consideration involves heavy tail and asymmetric outcomes. The case-deletion model (CDM) is considered, and several diagnostic measures are derived and discussed. Furthermore, we discuss score(More)
Lin and Wei [2003. Testing for heteroscedasticity in nonlinear regression models. Comm. Statist. Theory Methods 32, 171–192] developed the score test for heteroscedasticity in nonlinear regression models and investigated the power of this test through Monte Carlo simulations. The main purpose of this paper is to present an approach for estimating the local(More)
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