11  IQR (Inter Quartile Range)

The IQR (Inter Quartile Range) is the distance between the 25th percentile (Q1) and the 75th percentile (Q3). In a box plot, the whiskers usually extend \(1.5\times\)IQR beyond Q1 and Q3, see below.

Source: McDonald (2022)

A common outlier detection method is to consider whatever points outside the whisker range as outliers.