Palestrante: Prof. Ph.D. N. Balakrishnan - McMaster University Hamilton, Ontario, Canada
Título: Generalized gamma frailty model
Palestra Inaugural : Likelihood-based Inference for Mixed-Effects Models with Censored Response Using the Multivariate-t Distribution
Palestrante: Prof. Ph. D. Victor Hugo Lachos Davila - UNICAMP
Abstract: Mixed-effects models are commonly used to fit longitudinal or repeated measures data. A complication arises when the response is censored, for example, due to limits of quantification of the assay used. Although the normal distributions are commonly assumed for the random effects and the residual errors, such assumptions make inferences vulnerable in the presence of outliers. The sensitivity to outliers and the need of heavy tailed distributions for random effects and residual errors motivate us to develop a likelihood-based inference for linear and nonlinear mixed effects models with censored response (NLMEC/LMEC) based on the multivariate Student-t distribution. An ECM algorithm is developed for computing the maximum likelihood estimates for NLMEC/LMEC with the standard errors of the fixed effects and the likelihood function as a by-product. The algorithm uses the closed-form expressions at the E-step, which relies on the formulas of the mean and variance of a truncated multivariate-t distribution. The proposed algorithm is implemented in the R package tlmec. The proposed methodology is applied to analyze longitudinal HIV viral load data in the two recent AIDS studies. In addition, a simulation study is conducted to examine the performance of the proposed method and carry out the comparison with the approach by Vaida and Liu (2009).
(Joint work with Ming-Hiu Chen, Marcos Oliveira Prates and Larissa Avila Matos)
Palestra nº 2: Introdução ao mapeamento de QTL's.
Palestrante: Prof. Ph.D.Renato Rodrigues Silva – UFG
Palestra nº 3: Estatística e Big Data na Indústria e Agronegócio
Palestrante: Doris Satie Maruyama Fontes – Presidente do CONRE-3
Mini-Palestra nº 1: Estatística no Ministério Público de Goiás
Palestrante: Diego Gomes Martins do Carmo
Técnico em Estatística da Superintendência de Planejamento e Gestão
Mini-Palestra nº 2:
Palestrante: Mário Rodrigues Neto - Grupom Consultoria e Pesquisas.