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.