2.3 Pie charts and bar charts
The data set in Table 7 (section 1.8) comprised non-numerical or categorical data. Such data often appear in newspaper reports and are usually represented as one or other of two types of graphical display, one type is called a pie chart and the other a bar chart; these are arguably the graphical displays most familiar to the general public, and are certainly ones that you will have seen before. Pie charts are discussed in section 2.2 and bar charts in section 2.4. Some problems that can arise when using graphics of these types are discussed briefly in section 2.6.