### 7.1.7 The boxwhisker: boxwhisker mustache

A boxwhisker is a graphical view of the quartiles of a list of numbers.
The boxwhisker consists of a line segment from the the minimum of the
list to the first quartile, leading to a rectangle from the first
quartile to the third quartile, followed by a line segment from the
third quartile to the maximum of the list. The rectangle will contain
a vertical segment indicating the median, and the two line segments
will contain vertical lines indicating the first and ninth decile.

The boxwhisker (or mustache) command will create a
boxwhisker for a list. For example, if you enter

boxwhisker([-1,1,2,2.2,3,4,-2,5])

a graphic window will appear showing the boxwhisker,