We propose a U -statistics-based test for null variance components in linear mixed models and obtain its asymptotic distribution (for increasing number of units) under mild regularity conditions that include only the existence of the second moment for the random effects and of the fourth moment ...
The LR statistics under investigation here fall in thiscategory. Unfortunately, the assumed regularity conditions are not easily verified, especially when the covariance matrix of therandom effects is not diagonal as in linear mixed models with two correlated random effects. We show that such ...
Mixed models, with both random and fixed effects, are most often estimated on the assumption that the random effects are normally distributed. In this paper we propose several formal tests of the hypothesis that the random effects and/or errors are normally distributed. Most of the proposed metho...
GMMAT is an R package for performing association tests using generalized linear mixed models (GLMMs, seeBreslow and Clayton (1993)) in genome-wide association studies (GWAS) and sequencing association studies. First, GMMAT fits a GLMM with covariate adjustment and random effects to account for po...
LetN(μ;Σ) denote a multivariate Normal distribution with meansμand a variance-covariance matrixΣ. We wish to jointly test the association ofmgenetic variants with a quantitative traityfor a sample ofNobservations (i.e., participants) while controlling forqcovariates. Within the linear mixed mo...
He is responsible for national statistical data analyses and data management in various international large-scale assessments, e.g., PISA, TIMSS and PIRLS. His research interests include survey methodology, particularly in educational large-scale assessments, multilevel and linear mixed models in ...
Sensitivity and specificity were estimated directly using proportions and associated Wilson confidence intervals (CIs), and through two independents generalized (logistic) linear mixed models (GLMM) using the lme4 package in R25 when adjusting for different viral loads (measured through the proxy ...
With new implementation of the BOLT-LMM/MINQUE algorithm as well as a series of software engineering optimizations, our software package is capable of analyzing datasets of up to 1,000,000 individuals in linear mixed models on a computer workstation, which makes our tool one of the very few...
With new implementation of the BOLT-LMM/MINQUE algorithm as well as a series of software engineering optimizations, our software package is capable of analyzing datasets of up to 1,000,000 individuals in linear mixed models on a computer workstation, which makes our tool one of the very few...
Calculating Power for Testing Pairwise Contrasts of Fixed Effects in Mixed Models Mixed Model Theory and Notation A linear mixed model incorporates both fixed and random effects. Fixed effects are those effects in the model whose values are assumed constant, or unchanging. Random effects are those ...