outlier_plot {api2lm}

Index plot of studentized residuals for lm object

Description

outlier_plot plots the studentized residuals (from the rstudent function) of a fitted lm object.

Usage

outlier_plot(
  model,
  id_n = 3,
  add_reference = TRUE,
  alpha = 0.05,
  ...,
  text_arglist = list(),
  abline_arglist = list(),
  extendrange_f = 0.08
)

Arguments

model

A fitted model object from the lm function.

id_n

The number of points to identify with labels. The default is 3.

add_reference

A logical value indicating whether a reference line should be added. The default is TRUE. See Details.

alpha

The default lower quantile used for the reference line prior to the Bonferroni adjustment. The default is 0.05.

...

Additional arguments passed to the plot function.

text_arglist

Additional arguments passed to the text function, which is used to display the points that are identified.

abline_arglist

A named list specifying additional arguments passed to the abline function for the horizontal reference line added to the plot.

extendrange_f

Positive number(s) specifying the fraction by which the range of the residuals should be extended using the extendrange function. If longer than one, f[1] is used on the left and f[2] on the right.

Details

If add_reference = TRUE, then reference lines are provided for the \alpha/(2n and 1-\alpha/(2n) quantiles of a Student's t distribution with (df.residual(lmod) - 1) degrees of freedom, which are the standard quantiles used to identify outliers for a fitted model.

The vertical position of the reference line can be customized by setting the h argument of abline_arglist.

Author(s)

Joshua French

See Also

plot, text, abline, rstudent

Examples

lmod <- lm(price ~ sqft_living, data = home_sales)
outlier_plot(lmod, id_n = 1)