R lm
lm is a built-in R function for fitting linear models.
Contents
Example
mod <- lm(y ~ x)
Description
The lm function fits a linear model using 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 plot function.