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We consider an extension of linear mixed models by assuming a multivariate skew t distribution for the random effects and a multivariate t distribution for the error terms. The proposed model provides flexibility in capturing the effects of skewness and heavy tails simultaneously among continuous longitudinal data. We present an efficient alternating expectation-conditional maximization (AECM) algorithm for the computation of maximum likelihood estimates of parameters on the basis of two convenient hierarchical formulations. The techniques for the prediction of random effects and intermittent missing values under this model are also investigated. Our methodologies are illustrated through an application to schizophrenia data.
Department of Applied Mathematics, National Chung Hsing University, Taichung 402, Taiwan.
This article was published in the following journal.
Name: Biometrical journal. Biometrische Zeitschrift
Semiparametric mixed-effects joint models are flexible for modeling complex longitudinal-competing risks data. Skew distributions are commonly observed for this type of data. Covariates in the joint m...
This study had three purposes, all related to evaluating energy expenditure (EE) prediction accuracy from body-worn accelerometers: (1) compare linear regression to linear mixed models, (2) compare li...
Quantile regression (QR) models have recently received increasing attention in longitudinal studies where measurements of the same individuals are taken repeatedly over time. When continuous (longitud...
Tango (Biostatistics 2016) proposed a new repeated measures design called the S:T repeated measures design, combined with generalized linear mixed-effects models and sample size calculations for a tes...
In this article, we present a new method for optimizing designs of experiments for non-linear mixed effects models, where a categorical factor with covariate information is a design variable combined ...
Malaria is still endemic in the interior of French Guiana. mixed infections by 2 or more different malaria parasites lead to complex and potentially harmfull therapeutic problems. The aim ...
The purpose of this study is to evaluate the use and efficacy of the Encore Linear™ Hip System in a group of 200 patients for whom data has already been collected.
Linear ablation is frequently used in the procedure for persistent atrial fibrillation. However, it has a limitation because of technical difficulty. Incomplete block is common and an impo...
Acute upper-gastrointestinal bleeding (UGIB) is a commonly encountered cause of admission in emergency department (ED). Early risk stratification allows appropriate therapy that may be hel...
Robust I study is a feasibility study about safety and efficacy of DCB.
Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.
Statistical models of the production, distribution, and consumption of goods and services, as well as of financial considerations. For the application of statistics to the testing and quantifying of economic theories MODELS, ECONOMETRIC is available.
Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.
Statistical formulations or analyses which, when applied to data and found to fit the data, are then used to verify the assumptions and parameters used in the analysis. Examples of statistical models are the linear model, binomial model, polynomial model, two-parameter model, etc.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Schizophrenia is a common serious long-term mental health condition that affects 5 in 1000 in the UK. It causes a range of different psychological symptoms; hallucinations, delusions, muddled thoughts based on the hallucinations or delusions and ch...
Psychiatry is the study of mental disorders and their diagnosis, management and prevention. Conditions include schizophrenia, severe depression and panic disorders among others. There are pharmaceutical treatments as well as other therapies to help...