lmList {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)

[Package Contents]