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Scale mixture of skew-normal linear mixed models with within-subject serial dependence.
Schumacher, Fernanda L; Lachos, Victor H; Matos, Larissa A.
Afiliação
  • Schumacher FL; Department of Statistics, Universidade Estadual de Campinas, São Paulo, Brazil.
  • Lachos VH; Department of Statistics, University of Connecticut, Storrs, Connecticut, USA.
  • Matos LA; Department of Statistics, Universidade Estadual de Campinas, São Paulo, Brazil.
Stat Med ; 40(7): 1790-1810, 2021 03 30.
Article em En | MEDLINE | ID: mdl-33438305
In longitudinal studies, repeated measures are collected over time and hence they tend to be serially correlated. These studies are commonly analyzed using linear mixed models (LMMs), and in this article we consider an extension of the skew-normal/independent LMM, where the error term has a dependence structure, such as damped exponential correlation or autoregressive correlation of order p. The proposed model provides flexibility in capturing the effects of skewness and heavy tails simultaneously when continuous repeated measures are serially correlated. For this robust model, we present an efficient EM-type algorithm for parameters estimation via maximum likelihood and the observed information matrix is derived analytically to account for standard errors. The methodology is illustrated through an application to schizophrenia data and some simulation studies. The proposed algorithm and methods are implemented in the new R package skewlmm.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Algoritmos / Modelos Estatísticos Tipo de estudo: Observational_studies / Prognostic_studies / Risk_factors_studies Limite: Humans Idioma: En Revista: Stat Med Ano de publicação: 2021 Tipo de documento: Article País de afiliação: Brasil País de publicação: Reino Unido

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Algoritmos / Modelos Estatísticos Tipo de estudo: Observational_studies / Prognostic_studies / Risk_factors_studies Limite: Humans Idioma: En Revista: Stat Med Ano de publicação: 2021 Tipo de documento: Article País de afiliação: Brasil País de publicação: Reino Unido