The measurement scale of the Year data is nominal scale.
The strengths of this type of data are easy to order; Date categories are
represented by labels or names and there are no natural orders.
Chapter 2 assignment
1. The first table let us know a lot information that we need, such as lower, upper,
and midpoint, width, etc. And use accurate data of width to distribute six classes
which are very useful to make grahs
2. Using the histog