\Header{lmList}{List of lm Objects with a Common Model}
\methalias{lmList.formula}{lmList}
\alias{print.lmList}{lmList}
\alias{update.lmList}{lmList}
\keyword{models}{lmList}
\begin{Description}\relax
\code{Data} is partitioned according to the levels of the grouping
factor \code{g} and individual \code{lm} fits are obtained for each
\code{data} partition, using the model defined in \code{object}.
\end{Description}
\begin{Usage}
\begin{verbatim}
lmList(object, data, level, subset, na.action, pool)
## S3 method for class 'lmList':
update(object, formula, data, level, subset,
   na.action, pool, ...)
## S3 method for class 'lmList':
print(x, pool, ...)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{object}] For \code{lmList},
either a linear formula object of the form \code{y \textasciitilde{} x1+...+xn | g}
or a \code{groupedData} object. In the formula object, \code{y}
represents the response, \code{x1,...,xn} the covariates, and
\code{g} the grouping factor specifying the partitioning of the data
according to which different \code{lm} fits should be performed. The
grouping factor \code{g} may be omitted from the formula, in which
case the grouping structure will be obtained from \code{data}, which
must inherit from class \code{groupedData}. The method function 
\code{lmList.groupedData} is documented separately.
For the method \code{update.lmList}, \code{object} is an object
inheriting from class \code{lmList}.

\item[\code{formula}] (used in \code{update.lmList} only)
a two-sided linear formula with the common model for the individuals
\code{lm} fits.

\item[\code{data}] a data frame in which to interpret the variables named in
\code{object}. 

\item[\code{level}] an optional integer specifying the level of grouping to be used when 
multiple nested levels of grouping are present.

\item[\code{subset}] an optional expression indicating which subset of the rows of
\code{data} should  be  used in the fit. This can be a logical
vector, or a numeric vector indicating which observation numbers are
to be included, or a  character  vector of the row names to be
included.  All observations are included by default.
\item[\code{na.action}] a function that indicates what should happen when the
data contain \code{NA}s.  The default action (\code{na.fail}) causes
\code{lmList} to print an error message and terminate if there are any
incomplete observations.

\item[\code{pool}] an optional logical value indicating whether a pooled
estimate of the residual standard error should be used 
in calculations of standard deviations or standard errors for
summaries.

\item[\code{x}] an object inheriting from class \code{lmList} to be printed.
\item[\code{...}] some methods for this generic require additional
arguments.  None are used in this method.
\end{ldescription}
\end{Arguments}
\begin{Value}
a list of \code{lm} objects with as many components as the number of
groups defined by the grouping factor. Generic functions such as
\code{coef}, \code{fixed.effects}, \code{lme}, \code{pairs},
\code{plot}, \code{predict}, \code{random.effects}, \code{summary},
and \code{update} have methods that can be applied to an \code{lmList}
object.
\end{Value}
\begin{SeeAlso}\relax
\code{\Link{lm}}, \code{\Link{lme.lmList}}.
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
data(Orthodont)
fm1 <- lmList(distance ~ age | Subject, Orthodont)
summary(fm1)
\end{ExampleCode}
\end{Examples}

