Data Handling and Statistics
Outliers
An outlier is a data value that is unusually far from the rest of the dataset. A common rule identifies a value as an outlier if it lies more than 1.5 × IQR above Q3 or below Q1.
The 1.5 × IQR Rule
Upper boundary = Q3 + 1.5 × IQR. Lower boundary = Q1 − 1.5 × IQR. Any value beyond these boundaries is considered an outlier.
Practice: Outliers
Check whether a value is an outlier, or find an outlier boundary using the 1.5 x IQR rule.