The issue of variance components testing arises naturally when building mixed-effects models, to decide which effects should be modeled as fixed or random. While tests for fixed effects are available in R for models fitted with lme4, tools are missing when it comes to random effects. The varTestnlme package for R aims at filling this gap. It allows to test whether any subset of the variances and covariances corresponding to any subset of the random effects, are equal to zero using asymptotic property of the likelihood ratio test statistic. It also offers the possibility to test simultaneously for fixed effects and variance components. It can be used for linear, generalized linear or nonlinear mixed-effects models fitted via lme4, nlme or saemix. Theoretical properties of the used likelihood ratio test are recalled, numerical methods used to implement the test procedure are detailed and examples based on different real datasets using different mixed models are provided.

翻译：在建立混合效应模型时,自然会产生差异组成部分测试问题,以决定哪些效应应作为固定或随机模型进行模型。在R中,安装 lme4 模型的固定效应测试在随机效应时缺失工具。VarTesternlme R 软件包旨在填补这一空白。它允许测试与随机效应任何子集相应的差异和共变相是否等于零,使用概率比测试统计的无症状属性。它还提供同时测试固定效应和差异成分的可能性。它可用于安装 lme4 、 nlme 或 saemix 的线性、 通用线性线性或非线性混合效应模型。 使用的概率比测试的理论属性被回顾,用于实施测试程序的任何子集,详细列出用于实施测试程序的数字方法,并提供基于不同混合模型的不同真实数据集的实例。