Data Handling and Statistics
Interquartile Range (IQR)
The interquartile range (IQR) measures the spread of the middle 50% of a dataset: IQR = Q3 − Q1. Unlike the range, it isn't affected by extreme outliers.
Worked Example
If Q1 = 10 and Q3 = 22, then IQR = 22 − 10 = 12.
Practice: Interquartile Range
Compute the IQR from Q1 and Q3, or find it directly from a sorted dataset.