How to Increase the thickness of the box lines in an R boxplot?

Question

How can I increase the thickness of the lines that outline "box" part of a boxplot using either the base R plot or boxplot function? That is, how do I thicken the lines of the box that defines the quantiles.

For a plot like this:

boxplot(rnorm(100,50,10), horizontal = TRUE, notch = TRUE)

I'm guessing I need to include a pars = statement like

boxplot(rnorm(100,50,10), horizontal = TRUE, notch = TRUE, pars = ...)

EDIT: My guess regarding the use of pars = comes from a first glance at the documentation for boxplot which indicates that pars = can call "a list of (potentially many) more graphical parameters, eg, boxwex or outpch; these are passed to bxp (if plot is true)..."

Answer 1

See the boxlwd parameter as discussed in ?bxp (linked to from ?boxplot ). Eg

boxplot(rnorm(100,50,10), horizontal = TRUE, notch = TRUE, boxlwd = 4)

Answer 2

Are you talking about the rectangle that surrounds the plot area? If so, then this can follow you plot call:

 box(lwd=5)