plot_qq.lm: QQ-plot for an object of class 'lm'

In lmvar: Linear Regression with Non-Constant Variances

Description

Function produces QQ-plots for an object of class 'lm' and, optionally, for another object of class 'lm' or 'lmvar'.

Usage

## S3 method for class 'lm'
plot_qq(object_1, object_2 = NULL, ...)

Arguments

object_1	Object of class 'lm'
object_2	Object of class 'lm' or class 'lmvar'
...	for compatibility with plot_qq generic.

Details

If object_2 is specified, a QQ-plot for object_1 and one for object_2 will be combined in the same plot.

All inputs of class 'lm' must contain the response vector y. I.e., one must run lm with argument y = TRUE.

See Also

plot_qq

Examples

if (interactive()){

library(lmvar)

# create a linear model using the 'iris' data set
fit_lm = lm( Petal.Length ~ Species, data = iris, y = TRUE)

plot_qq(fit_lm)

# compare 'lm' with 'lmvar' fit
X = model.matrix(~ Species - 1, data = iris)
fit_lmvar = lmvar(iris$Petal.Length, X, X)

plot_qq(fit_lm, fit_lmvar)

# check whether inclustion of petal in model improves QQ-plot
fit_lm_width = lm( Petal.Length ~ Species + Petal.Width, data = iris, y = TRUE)

plot_qq(fit_lm, fit_lm_width)

}

lmvar documentation built on May 16, 2019, 5:06 p.m.