MATLAB: Is there a way to create a boxplot in MATLAB 7.7 (R2008b) so that the notches are less unattractive

Question

When I create a boxplot in MATLAB 7.7 (R2008b), I dislike the apperance of the notches when they extend outside the box. I want an alternative boxplot that looks more attractive.

Reproduction code:

load hogg
boxplot(hogg,'notch','on')

Answer 1

This change has been incorporated into the documentation in Release 2009b (R2009b). For previous releases, read below for any additional information:

The notches on a boxplot made in MATLAB 7.7 (R2008b) are intended to give an indication of the uncertainty in estimating the median. They can be used to do a graphical comparison of whether one median is significantly different from another.

If you wish to create a boxplot without the notches, use the 'marker' option that uses triangle markers to indicate notch positions as shown below:

load hogg
boxplot(hogg,'notch','marker')

Tukey (inventor of the box plot) and co-authors show this display in the paper "Variations of Box Plots," Robert McGill, John W. Tukey, and Wayne A. Larsen, ''The American Statistician'', Vol. 32, No. 1. (Feb., 1978), pp. 12-16. See figure F of that paper.

Note that for the above method, the comparison intervals are the ones that extend between the centers of the two triangles.