This method function extracts the covariate(s) associated with the
variance function represented by
object, if any is present.
an object inheriting from class
an optional formula specifying the covariate to be
some methods for this generic require a
object has a
covariate attribute, its value is
NULL is returned.
José Pinheiro and Douglas Bates [email protected]
1 2 3
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.