### 7.1.9 Histograms: histogram histogramme

Given a list of intervals and a number of points in each interval,
such as is given by the output of the classes command, the
histogram (or histogramme) command will draw a box
over each interval so that the height of each box is proportional to
the number of points and the total area of the boxes is 1. For
example, if you enter

histogram([[1.5..1.65,50],[1.65..1.7,20],[1.7..1.8,30]])

you will get

If you just give the histogram a list of numbers, or a list
with values a and b, then you will get the histogram of the result
of applying classes to the list.
For example, if you enter

histogram([1,2,2.5,2.5,3],0.5,0.75)

you will get