The predictions at level i are obtained by adding together the
population predictions (based only on the fixed effects estimates)
and the estimated contributions of the random effects to the
predictions at grouping levels less or equal to i. The resulting
values estimate the best linear unbiased predictions (BLUPs) at level
i. If group values not included in the original grouping factors
are present in
newdata, the corresponding predictions will be
set to
NA for levels greater or equal to the level at which the
unknown groups occur.
an object inheriting from class
lme, representing
a fitted linear mixed-effects model.
OPTIONAL ARGUMENTS:
newdata
an optional data frame to be used for obtaining the
predictions. All variables used in the fixed and random effects
models, as well as the grouping factors, must be present in the data
frame. If missing, the fitted values are returned.
level
an optional integer vector giving the level(s) of grouping
to be used in obtaining the predictions. Level values increase from
outermost to innermost grouping, with level zero corresponding to the
population predictions. Defaults to the highest or innermost level of
grouping.
asList
an optional logical value. If
TRUE and a single
value is given in
level, the returned object is a list with
the predictions split by groups; else the returned value is
either a vector or a data frame, according to the length of
level.
na.action
a function that indicates what should happen when
newdata contains
NAs. The default action
(
na.fail) causes the function to print an error message and
terminate if there are any incomplete observations.
VALUE:
if a single level of grouping is specified in
level, the
returned value is either a list with the predictions split by groups
(
asList = TRUE) or a vector with the predictions
(
asList = FALSE); else, when multiple grouping levels are
specified in
level, the returned object is a data frame with
columns given by the predictions at different levels and the grouping
factors.