Statistics & Probability
Intermediate
Interquartile Range
The spread of the middle 50% of the data.
Formula
Variables
Q_1First quartile
Q_3Third quartile
Example
If Q₁ = 20 and Q₃ = 35, the interquartile range is 35 − 20 = 15.
Did You Know?
The interquartile range is the backbone of the box plot and a robust way to spot outliers.