Interquartile Range

Interquartile ranges describe the spreads of numbers. They are the differences in the medians of the upper and lower halves after discarding medians for odd quantities. For example, the interquartile range of {1, 11, 15, 19, 20, 24, 28, 34, 37, 47, 50, 57} is 42 - 17 or 25. The interquartile range of {63, 64, 64, 70, 72, 76, 77, 81, 81} is 79 - 64 or 15.