What is the role of Interquartile Range (IQR) in anomaly detection?

Updated May 5, 2026

Short answer

It defines boundaries based on the middle 50% of the data[cite: 1].

Deep explanation

Outliers are points falling below Q1 - 1.5IQR or above Q3 + 1.5IQR[cite: 1].

Real-world example

Box plots used to show data spread and outliers[cite: 1].

Common mistakes

  • Using 1.5 as a universal constant for all data types[cite: 1].

Follow-up questions

  • Difference between IQR and Z-score?

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