Statistics & Probability

Interquartile range (IQR)

A measure of spread: Q3 − Q1. Less sensitive to outliers than the range.

Definition

Q1 (lower quartile) is the value 25% of the way through sorted data; Q3 (upper quartile) is at 75%. The IQR captures the middle half of the data.

Used in these topics

Related terms

Quartile

The values that split sorted data into four equal parts. Q1 (25%), Q2 (median, 50%), Q3 (75%).

Range

A measure of spread: largest value minus smallest value.

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