This chapter discussed graphical descriptive methods used to summarize and describe sets of data. This section introduced the two main types of data that are referred to throughout the text: quantitative (numerical) data and qualitative (categorical) data. The appropriate graphical method to be used in presenting data depends, in part, on the type of data under consideration. Later in the text, when statistical inference is covered, the data type will help to identify the appropriate statistical technique to be used in solving a problem. In a few situations, it will be necessary to recognize whether or not a set of nonquantitative data can be ordered. If the categories for a set of nonquantitative data can be ordered or ranked, we have a third type of data, called ranked data. At the completion of this section, you should be able to identify whether the type of data under con- sideration is quantitative, qualitative, or ranked.