Mixed Models

Mixed linear models (MLM) are an extension of linear models that include both fixed and random effects and are particularly used when there is no independence in the data, such as arises from a hierarchical structure. For example, plants from a particular crop could be sampled within plots, students evaluated within classrooms, cattle studied within a herd, varieties evaluated within blocks, even the same individual evaluated at various points on a timeline, etc. Mixed linear models allow effectively modeling data that are not independent. Of course, this statement is quite general, and the actual use of mixed models (MM) varies widely among fields of study. The data suitable for analysis through mixed models usually have some hierarchical.