Step 2: Determine the width of the classes.
It is very wise to make classes of uniform width.
Approximate class width = (maximum value - minimum value)/Number of classes
In our example, (116-85.1)/5 = 6.18. You should always round up, using classes 7 cents wide.
Some might argue that a good idea would be to use either 5 or 10 cents as a width because people think in terms of 5-cent increments. This is a judgement call. I’ll use 7 cents.