level
an optional integer vector giving the level(s) of grouping
to be used in extracting the fitted values from object
. Level
values increase from outermost to innermost grouping, with
level zero corresponding to the population fitted val
asList
an optional logical value. If TRUE
and a single
value is given in level
, the returned object is a list with
the fitted values split by groups; else the returned value is
either a vector or a data frame, according to the