### 2.2 Summarising data that are ordinal or scale

Where ordinal or discrete- or continuous- scale data are to be displayed, the most appropriate graphical presentation is a histogram (Fig. 4) where there is a relatively small data range and data are ordinal or discrete, or a continuous distribution curve in the case of continuous scale data with a wide range. A histogram works in the same way as a bar chart, but there is no space between the bars. It is the area of the histogram bar that signifies the value, not its height, and histogram bars may encompass different data ranges.

**Figure 4.** An example of a histogram used to show a frequency distribution