A variable, in turn, need not be univariate, they can also be multivariate. In this case, they will also occupy multiple columns in a model matrix.
If one or more of the terms is a factor, the term will be expanded into several columns within the model matrix.
Examples of terms:
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|