13.8 Summary

Quantitative data can be summarised numerically, and the most common techniques are indicated in Table 13.9. The mean and standard deviation are usually used whenever possible, for practical and mathematical reasons. Sometimes quoting both the mean and median (and the standard deviation and IQR) may be appropriate.

The following short video may help explain some of these concepts:

TABLE 13.9: Summarising quantitative data
For distributions that are:
Feature: Approximately symmetric Not symmetric, or outliers
Average: Mean Median
Variation: Standard deviation IQR
Shape: Verbal description only Verbal description only
Outliers: Standard deviation rule IQR rule