Stats: What is an interquartile range?

What is an interquartile range?

The interquartile range (IQR) is the distance between the 75th percentile and the 25th percentile. The IQR is essentially the range of the middle 50% of the data. Because it uses the middle 50%, the IQR is not affected by outliers or extreme values.

The IQR is also equal to the length of the box in a box plot.

via Stats: What is an interquartile range?.