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.

Upper boundary = Q3 + 1.5 × IQR. Lower boundary = Q1 − 1.5 × IQR. Any value beyond these boundaries is considered an outlier.

Check whether a value is an outlier, or find an outlier boundary using the 1.5 x IQR rule.

Continue exploring related topics:

• Interquartile Range - Measuring the Middle Spread
• Box-and-Whisker Plots - Visualising Quartiles
• Data Distribution - Shape and Skew