Outliers

Math

Definition

Data points that are significantly different from the rest of the dataset. A common rule identifies outliers as values more than 1.5 times the interquartile range (IQR) below Q1 or above Q3.

Examples

  • In test scores of 85, 88, 90, 92, 45, the score of 45 is an outlier
  • A salary of $2 million in a dataset of middle-class incomes
  • A 7-foot-tall student in an elementary school class
Key Fact

Outlier if value < Q1 - 1.5(IQR) or value > Q3 + 1.5(IQR)

Related Terms

Mean median mode Standard deviation Scatter plots

Study This Concept

Practice outliers with free review games in these units:

AP Statistics Unit 1: Exploring One-Variable Data