lmList {lme4} | 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(formula, data, level, subset, na.action, pool)

### Arguments

`formula` | For `lmList`, a linear formula object of the form `y ~ x1+...+xn | g`. 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`.
`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 that is preserved as an attribute of the returned value. This will be used as the default for `pool` in calculations of standard deviations or standard errors for summaries.

### Value

an object of class lmList which is a list of `lm` objects with as many components as the number of groups defined by the grouping factor.

### See Also

`lm`

### Examples

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

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