[R] boxplot notches

[Thomas Lumley]

On Tue, 2 Mar 2004, P. B. Pynsent wrote:

> A Google search showed  that all this was discussed in April 1988 with
> an extensive reply to the question from M Maechler.
> I, as a non-statistician, blindly believed what was written in the
> boxplot() help file, I am sure many would be grateful to this help
> being modified.
>
> I still do not understand why , 6 years later with GHz processors,
> boxplot() could not have an option to produce exact intervals. After
> all,  a range option is offered for the whiskers.
> At least then non-overlapping notches would have some meaning, wouldn't
> they?

Well, they would have *some* meaning, but it would be hard to say exactly
what. There isn't an exact confidence interval for  the difference in
medians, so you can't find a level for two confidence intervals that
corresponds to a specified level for the test of equality of medians.

	-thomas