The Unit Weibull Regression Model with Variable Shape Parameter

Lucas  David Ribeiro-Reis

Authors

Lucas David Ribeiro-Reis Faculty of Statistics, Institute of Exact and Natural Sciences, Federal University of Para, Belem-PA, Brazil

Keywords:

median, maximum likelihood, Bounded data analyses, regression model, Northeast of the Brazil, Covid-19

Abstract

In this paper a generalization of the unit Weibull regression model is introduced. Here, both the median and the shape parameter are modelled through covariates. The parameters are estimated by maximum likelihood. Analytical expressions for the score vector and the Fisher’s observed information matrix are demonstrated. A simulation study is performed to show the consistency of the maximum likelihood estimators. Finally two applications to real data from Brazil are considered. These applications show the usefulness of the proposed model.

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