1. The central half of a data set typically refers to the middle 50% of the data when it is ordered from smallest to largest. 2. This is often represented by the interquartile range (IQR), which is the difference between the third quartile ($Q_3$) and the first quartile ($Q_1$). 3. The first quartile ($Q_1$) is the median of the lower half of the data, and the third quartile ($Q_3$) is the median of the upper half. 4. The IQR shows the spread of the middle 50% of the data, giving a measure of variability that is not affected by extreme values or outliers. 5. In summary, the central half of the data shows the range within which the central 50% of values lie, providing insight into the data's dispersion and central tendency.