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 o

Answer 1

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

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)