In these pages, we are concerned with two ways of representing descriptive statistics: numerical and pictorial.
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.
Taking numerical data and presenting it in pictures or graphs is known as 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.