Box Plot

http://support.sas.com/documentation/cdl/en/statug/63033/HTML/default/viewer.htm#statug_boxplot_sect005.htm

Box plots are used to show the 5 number summary of data on a graph so people can more easily learn multiple things about the data. The bottom line shows the lowest number, the box is where 50% of the data is, top line is the highest number, and the middle line is the average. In a box plot you can learn all 5 of these things with one graph. The above graph shows the monthly power output, it is very useful in the situation of tracking the amount of data.