In-House Counsel

Box-and-whisker plots to compactly display much data

By Rees Morrison

An excellent way to portray data from a collection is the box-and-whisker plot. The box in the middle shows by its top line the third quartile figure in the collection, where 25 percent of the data points in the sample are higher than this value. Above it, a line extends upward to another line parallel to the top of the box, which marks the maximum value in the collection. That is the top whisker.

Somewhere inside the box a hyphenated line shows the median. The bottom line of the box shows the first quartile figure. A line extending down that goes to another perpendicular line that shows the minimum value in a sample., where half of the data points in the sample or higher and half are lower.

Thus from the top down the box-and-whisker shows the maximum value, the third quartile, the median, the first quartile, and the minimum value. An excellent tool for data visualization (See my post of May 7, 2008: methods to portray data with 9 references and 22 cited in one of them.).

Full post as published by Law Department Management on January 15, 2009 (boomark / email).