In these pages, we are concerned with two ways of representing descriptive statistics: numerical and pictorial.

Numerical statistics

**Numerical statistics** are numbers, but clearly, some numbers are more meaningful than others. For example, if you are offered a purchase price of $1 for an automobile on the condition that you also buy a second automobile, the price of the second automobile would be a major consideration (its price could be $1,000,000 or $1,000); thus, the average—or **mean**—of the two prices would be the important statistic.

Pictorial statistics

**pictorial statistics**. Showing data in the form of a graphic can make complex and confusing information appear more simple and straight‐forward. Different types of graphs are used for quantitative and categorical variables.