A box plot or a box and whisker plot is a graphic form used to plot the median, minimum, maximum, quartiles, and outliers for one or more data sets. A box plot allows you to focus on the relative position of different sets of data and thereby compare them more easily. Box plots are best used when the set of data contains hundreds of numbers. This box plot graph displays the injury ratings for compact, midsize, and large cars. Which car size would you purchase?

Note: The cars are rated in relative terms; 100 represents the average for all cars. Lower numbers mean a better safety record. A rating of 121, for example, means 21% worse than the average.

Unlike the stem and leaf graph, the box plot does not display individual points, but rather, concentrates on specific points including the median, quartiles, and extremes. This can be very useful especially if you use large data sets.