Inter-quartile range is the difference between the first and the third quartiles. It is a descriptive statistic that measures the dispersion of a dataset.

Example 1:

For the dataset of 6, 2, 13, 17 and 22. The 1st and 3rd quartiles can be calculated as 5.75 and 17.25, respectively. Then the inter-quartile range is 17.25 - 5.75 = 11.5.

Example 2:

For the dataset of 6, 2, 13, 17, 22 and 900. The 1st and 3rd quartiles can be calculated as 6 and 22, respectively.

Then the inter-quartile range is 22 - 6 = 16.