Box plot

A box plot summarizes a data set using its five-number-summary. A box runs from the first quartile to the third, with a line at the median; whiskers extend to the minimum and maximum.

Because it is built from the five-number summary, a box plot shows the spread and the position of the middle half of the data at a glance. The width of the box is the interquartile-range, a measure of spread that ignores the extremes.