Supported by the National Natural Science Foundation of China (No. 11001267);the Fundamental Research Funds for the Central Universities in China (No. 2009QS02);Supported by the National Natural Science Foundation of China (No. 10701079, 10871001)
Linear mixed models (LMMs) have become an important statistical method for analyzing cluster or longitudinal data. In most cases, it is assumed that the distributions of the random effects and the errors are normal....