期刊名称：Brazilian Journal of Probability and Statistics
印刷版ISSN：0103-0752
出版年度：2001
卷号：15
期号：2
页码：147-154
出版社：Brazilian Statistical Association
摘要：The poly-Weibull model is a general family which can accommodate not only con-stant, increasing or decreasing hazard curves with zero or non zero asymptotes,but also nonmonotones ones, including bathtub-shaped. In this paper we considerthe non-identifiability problem, which arises when the shape parameters of a poly-Weibull model are close. A graphical method based on the total-time-on-test plotand its simulated envelop is considered for detecting when a poly-Weibull modelis likely to be identifiable. We also provide a general framework for construct-ing hypothesis tests for non-identifiability by using parametric bootstrap-basedmetho ds. We set up a simulation study and show that the bootstrap tests havedesirable properties with respect to size and power
关键词：Bi-Weibull model; hazard mo dels; hypothesis tests; non-identifia-;bility; TTT plot
