dffits_test: Identify influential observations

In api2lm: Functions and Data Sets for the Book "A Progressive Introduction to Linear Models"

Identify influential observations

Description

dffits_test returns the observations identified as influential based on the absolute value of the DFFITS statistics being larger than a threshold.

The threshold used is 2\sqrt{p/n}, where p = length(stats::coef(model)) and n = stats::nobs(model).

Usage

dffits_test(model, n = stats::nobs(model))

Arguments

model	A fitted model object from the lm function.
n	The number of outliers to return. The default is all influential observations.

Value

A vector of influential observations.

See Also

dffits

Examples

lmod <- lm(price ~ sqft_living, data = home_sales)
dffits_test(lmod)

api2lm documentation built on July 9, 2023, 5:52 p.m.