s20x (version 3.1-40)

cooks20x: Cook's distance plot

Description

Draws a Cook's distance plot.

Usage

cooks20x(
  x,
  main = "Cook's Distance plot",
  xlab = "observation number",
  ylab = "Cook's distance",
  line = c(0.5, 1.2, 2),
  cex.labels = 1,
  axisOpts = list(xAxis = TRUE, yAxisTight = FALSE),
  ...
)

Value

Returns the plot and identifies the three highest Cook's values

Arguments

x

an object of class lm, usually obtained by using the lm function.

main

the plot title

xlab

the x-axis title.

ylab

the y-axis title.

line

a vector of length 3 controlling the distances of the plot title, the x-axis title and the y-axis title from the axis in line units.

cex.labels

a factor controlling the font size of the labels on suspected high influence points.

axisOpts

a list of additional arguments that can be used to control the axes. At this point this list only contains one element xAxis which is logical. If xAxis == TRUE then the x-axis will be displayed, and clearly, if it is FALSE, then it will not.

...

additional arguments are passed to plot and may provide some extra flexibility.

Examples

# Peruvian Indians data
data(peru.df)
peru.fit = lm(BP ~ age + years + I(years^2) + weight + height, data = peru.df)
cooks20x(peru.fit)