Box and Whisker Plots: Displaying Mean, Interquartile Range, and Range

摘要

A challenge for researchers is to present their findings so that it will be useable and understandable to the reader. Often visual representations assist the reader in understanding thefindings, especially when groups are being compared. A box and whisker plot is a useful visual representation when (a) large numbers of observations are measured on an interval scaie (the distance between points on the scale are equal, such as test scores, temperatures), (b) when two or more groups being compared, and (c) when the scores are not normally distributed. The box and whisker plot (also called a box plot) allows immediate visualization of the center and spread of the scores. The statistics presented include the median (center) and two measures of spread or variability, the interquartile range and the overall range of scores. The components of the box and whisker plot are illustrated below.