| Texto completo | |
| Autor(es): |
Matos, Larissa A.
;
Castro, Luis M.
;
Lachos, Victor H.
Número total de Autores: 3
|
| Tipo de documento: | Artigo Científico |
| Fonte: | TEST; v. 25, n. 4, p. 627-653, DEC 2016. |
| Citações Web of Science: | 2 |
| Resumo | |
In some acquired immunodeficiency syndrome (AIDS) clinical trials, the human immunodeficiency virus-1 ribonucleic acid measurements are collected irregularly over time and are often subject to some upper and lower detection limits, depending on the quantification assays. Linear and nonlinear mixed-effects models, with modifications to accommodate censored observations, are routinely used to analyze this type of data (Vaida and Liu, J Comput Graph Stat 18:797-817, 2009; Matos et al., Comput Stat Data Anal 57(1):450-464, 2013a). This paper presents a framework for fitting LMEC/NLMEC with response variables recorded at irregular intervals. To address the serial correlation among the within-subject errors, a damped exponential correlation structure is considered in the random error and an EM-type algorithm is developed for computing the maximum likelihood estimates, obtaining as a byproduct the standard errors of the fixed effects and the likelihood value. The proposed methods are illustrated with simulations and the analysis of two real AIDS case studies. (AU) | |
| Processo FAPESP: | 14/02938-9 - Estimação e diagnóstico em modelos de efeitos mistos para dados censurados usando misturas de escala skew-normal |
| Beneficiário: | Víctor Hugo Lachos Dávila |
| Linha de fomento: | Auxílio à Pesquisa - Regular |
| Processo FAPESP: | 11/22063-9 - Aplicações das distribuições de misturas da escala skew-normal em modelos de análise fatorial |
| Beneficiário: | Larissa Avila Matos |
| Linha de fomento: | Bolsas no Brasil - Doutorado |