lmList                 package:nlme                 R Documentation

List of lm Objects with a Common Model

Description:

     'Data' is partitioned according to the levels of the grouping
     factor 'g' and individual 'lm' fits are obtained for each 'data'
     partition, using the model defined in 'object'.

Usage:

     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, ...)

Arguments:

  object: For 'lmList', either a linear formula object of the form 'y ~
          x1+...+xn | g' or a 'groupedData' object. In the formula
          object, 'y' represents the response, 'x1,...,xn' the
          covariates, and 'g' the grouping factor specifying the
          partitioning of the data according to which different 'lm'
          fits should be performed. The grouping factor 'g' may be
          omitted from the formula, in which case the grouping
          structure will be obtained from 'data', which must inherit
          from class 'groupedData'. The method function 
          'lmList.groupedData' is documented separately. For the method
          'update.lmList', 'object' is an object inheriting from class
          'lmList'. 

 formula: (used in 'update.lmList' only) a two-sided linear formula
          with the common model for the individuals 'lm' fits. 

    data: a data frame in which to interpret the variables named in
          'object'.  

   level: an optional integer specifying the level of grouping to be
          used when  multiple nested levels of grouping are present. 

  subset: an optional expression indicating which subset of the rows of
          '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.

na.action: a function that indicates what should happen when the data
          contain 'NA's.  The default action ('na.fail') causes
          'lmList' to print an error message and terminate if there are
          any incomplete observations. 

    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. 

       x: an object inheriting from class 'lmList' to be printed.

     ...: some methods for this generic require additional arguments. 
          None are used in this method.

Value:

     a list of 'lm' objects with as many components as the number of
     groups defined by the grouping factor. Generic functions such as
     'coef', 'fixed.effects', 'lme', 'pairs', 'plot', 'predict',
     'random.effects', 'summary', and 'update' have methods that can be
     applied to an 'lmList' object.

See Also:

     'lm', 'lme.lmList'.

Examples:

     data(Orthodont)
     fm1 <- lmList(distance ~ age | Subject, Orthodont)
     summary(fm1)

