= R lm =

'''`lm`''' is a built-in R function for fitting linear models.

<<TableOfContents>>

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== Example ==

{{{
mod <- lm(y ~ x)
}}}

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== Description ==

The `lm` function fits a linear model using [[Statistics/OrdinaryLeastSquares|OLS]]. The LHS and RHS of the model are delimited by a tilde (`~`), as in `y ~ x`. For a model fit by `lm`, there should only be one (dependent) variable on the LHS.

The RHS is a linear combination of parameters, like `a + b + c`. The intercept term is implicit but can be omitted by specifying a literal `0` or `-1` on the LHS. For example, ` y ~ 0 + x`.

An interaction term is specified like `factor1:factor2`. Further note that `factor1 * factor2` is a shorthand for `factor1 + factor2 + factor1:factor2`.

If the `data` option is specified, names are looked up as columns in there first.

{{{
mod <- lm(foo ~ bar, data=df)
}}}

`lm` returns an object that can be passed to the [[R/BuiltinFunctions/Plot#lm|plot]] function.



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