Definition The spread of the middle half of values, from the 25th percentile to the 75th percentile.
Also called IQR, Interquartile range
Example If the 25th percentile delivery time is 2 days and the 75th is 5 days, the IQR is 3 days.
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Why it matters It shows typical spread without being distorted by extreme values.
Where it is used Box plots and statistical reports.
How to calculate it 75Th percentile − 25th percentile
Worked example If the 25th percentile delivery time is 2 days and the 75th is 5 days, the IQR is 3 days.
