masterThesis
Avaliação e correções de testes de hipóteses em modelos de sobrevivência com fração de cura
Fecha
2016-02-15Registro en:
LOOSE, Laís Helen. Avaliação e correções de testes de hipóteses em modelos de sobrevivência com fração de cura. 2016. 54f. Dissertação (Mestrado em Matemática Aplicada e Estatística) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2016.
Autor
Loose, Laís Helen
Resumen
Survival models deals with the modelling of time to event data. In certain situations,
a share of the population can no longer be subjected to the event occurrence.
In this context, the cure fraction models emerged. Among the models that incorporate
a fraction of cured one of the most known is the promotion time model. In the
present study we discuss hypothesis testing in the promotion time model with Weibull
distribution for the failure times of susceptible individuals. Hypothesis testing in this
model may be performed based on likelihood ratio, gradient, score or Wald statistics.
The critical values are obtained from asymptotic approximations, which may result in
size distortions in nite sample sizes. This study proposes bootstrap corrections to the
aforementioned tests and Bartlett bootstrap to the likelihood ratio statistic in Weibull
promotion time model. Using Monte Carlo simulations we compared the nite sample
performances of the proposed corrections in contrast with the usual tests. The numerical
evidence favors the proposed corrected tests. At the end of the work an empirical
application is presented.