Extract groupedData Formula

DESCRIPTION:

This method function extracts the display formula associated with a groupedData object. This is a two-sided formula of the form resp ~ cov | group, where resp is the response, cov is the primary covariate, and group is the grouping structure.

USAGE:

formula(object) 

REQUIRED ARGUMENTS:

object
an object inheriting from class groupedData.

VALUE:

a two-sided formula with a conditioning expression, representing the display formula for object.

SEE ALSO:

EXAMPLES:

formula(Orthodont)