ABSTRACT
In this chapter, we illustrate the analysis of a two-level clustered data set. Such data sets typically include randomly sampled clusters (Level 2) and units of analysis (Level 1), which are randomly selected from each cluster. Covariates can measure characteristics of the clusters or of the units of analysis, so they can be either Level 2 or Level 1 variables. The dependent variable, which is measured on each unit of analysis, is always a Level 1 variable.
