scispace - formally typeset
Open AccessJournal ArticleDOI

Fitting Linear Mixed-Effects Models Using lme4

TLDR
In this article, a model is described in an lmer call by a formula, in this case including both fixed-and random-effects terms, and the formula and data together determine a numerical representation of the model from which the profiled deviance or the profeatured REML criterion can be evaluated as a function of some of model parameters.
Abstract
Maximum likelihood or restricted maximum likelihood (REML) estimates of the parameters in linear mixed-effects models can be determined using the lmer function in the lme4 package for R. As for most model-fitting functions in R, the model is described in an lmer call by a formula, in this case including both fixed- and random-effects terms. The formula and data together determine a numerical representation of the model from which the profiled deviance or the profiled REML criterion can be evaluated as a function of some of the model parameters. The appropriate criterion is optimized, using one of the constrained optimization functions in R, to provide the parameter estimates. We describe the structure of the model, the steps in evaluating the profiled deviance or REML criterion, and the structure of classes or types that represents such a model. Sufficient detail is included to allow specialization of these structures by users who wish to write functions to fit specialized linear mixed models, such as models incorporating pedigrees or smoothing splines, that are not easily expressible in the formula language used by lmer.

read more

Content maybe subject to copyright    Report

Citations
More filters
Journal ArticleDOI

Mindfulness Meditation and Cognitive Behavioral Therapy Intervention Reduces Pain Severity and Sensitivity in Opioid-Treated Chronic Low Back Pain: Pilot Findings from a Randomized Controlled Trial.

TL;DR: Meditation-CBT intervention reduced pain severity and sensitivity to experimental thermal pain stimuli in patients with opioid-treated chronic low back pain in a 26-week pilot randomized controlled trial.
Journal ArticleDOI

Seasonal abundance and survival of North America's migratory avifauna determined by weather radar.

TL;DR: It is shown that, relative to biomass leaving in autumn, proportionally more biomass returned in spring across the southern United States than across the northern United States, providing a picture of survival rates for species with different life-history and migratory strategies.
Journal ArticleDOI

High-Resolution Genome-wide Association Study Identifies Genomic Regions and Candidate Genes for Important Agronomic Traits in Wheat.

TL;DR: Results from this study demonstrated that significantly increasing GWAS population size and marker density greatly improves detection and identification of candidate genes underlying a QTL, solidifying the foundation of large-scale QTL fine mapping, candidate gene validation, and developing functional markers for genomics-based breeding in wheat.
Journal ArticleDOI

Variability of Bacterial Communities in the Moth Heliothis virescens Indicates Transient Association with the Host

TL;DR: In larvae, bacterial communities differed depending on the food plant on which they had been reared, although the within-group variation between biological replicates was high, and the high variability in bacterial communities suggests a loose and temporary association of the identified bacteria with H. virescens.
References
More filters
Journal Article

R: A language and environment for statistical computing.

R Core Team
- 01 Jan 2014 - 
TL;DR: Copyright (©) 1999–2012 R Foundation for Statistical Computing; permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and permission notice are preserved on all copies.
Book

Bayesian Data Analysis

TL;DR: Detailed notes on Bayesian Computation Basics of Markov Chain Simulation, Regression Models, and Asymptotic Theorems are provided.
Book

Mixed-Effects Models in S and S-PLUS

TL;DR: Linear Mixed-Effects and Nonlinear Mixed-effects (NLME) models have been studied in the literature as mentioned in this paper, where the structure of grouped data has been used for fitting LME models.
Book

Data Analysis Using Regression and Multilevel/Hierarchical Models

TL;DR: Data Analysis Using Regression and Multilevel/Hierarchical Models is a comprehensive manual for the applied researcher who wants to perform data analysis using linear and nonlinear regression and multilevel models.