The estimated coefficients at level \(i\) are obtained by adding together the fixed effects estimates and the corresponding random effects estimates at grouping levels less or equal to \(i\). The resulting estimates are returned as a data frame, with rows corresponding to groups and columns to coefficients. Optionally, the returned data frame may be augmented with covariates summarized over groups.
# S3 method for lme
coef(object, augFrame, level, data, which, FUN,
omitGroupingFactor, subset, …)an object inheriting from class "lme", representing
a fitted linear mixed-effects model.
an optional logical value. If TRUE, the returned
data frame is augmented with variables defined in data; else,
if FALSE, only the coefficients are returned. Defaults to
FALSE.
an optional positive integer giving the level of grouping to be used in extracting the coefficients from an object with multiple nested grouping levels. Defaults to the highest or innermost level of grouping.
an optional data frame with the variables to be used for
augmenting the returned data frame when augFrame =
TRUE. Defaults to the data frame used to fit object.
an optional positive integer or character vector
specifying which columns of data should be used in the
augmentation of the returned data frame. Defaults to all columns in
data.
an optional summary function or a list of summary functions
to be applied to group-varying variables, when collapsing data
by groups. Group-invariant variables are always summarized by the
unique value that they assume within that group. If FUN is a
single function it will be applied to each non-invariant variable by
group to produce the summary for that variable. If FUN is a
list of functions, the names in the list should designate classes of
variables in the frame such as ordered, factor, or
numeric. The indicated function will be applied to any
group-varying variables of that class. The default functions to be
used are mean for numeric factors, and Mode for both
factor and ordered. The Mode function, defined
internally in gsummary, returns the modal or most popular
value of the variable. It is different from the mode function
that returns the S-language mode of the variable.
an optional logical value. When TRUE
the grouping factor itself will be omitted from the group-wise
summary of data but the levels of the grouping factor will
continue to be used as the row names for the returned data frame.
Defaults to FALSE.
an optional expression specifying a subset
some methods for this generic require additional arguments. None are used in this method.
a data frame inheriting from class "coef.lme" with the estimated
coefficients at level level and, optionally, other covariates
summarized over groups. The returned object also inherits from classes
"ranef.lme" and "data.frame".
Pinheiro, J. C. and Bates, D. M. (2000), Mixed-Effects Models in S and S-PLUS, Springer, New York, esp. pp. 455-457.
# NOT RUN {
fm1 <- lme(distance ~ age, Orthodont, random = ~ age | Subject)
coef(fm1)
coef(fm1, augFrame = TRUE)
# }
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