Box plot - Text Anxiety

http://onlamp.com/pub/a/php/2004/07/22/php_anova.html?page=3

Box plots are able to describe a set of data through 5 numerical values: the lowest value recorded, the lower quartile, median, the upper quartile, and the highest value recorded.  These plots help to show us the degree of dispersion within the data and the skewness.

In the box and whisker plots shown above, test scores are reported under varying levels of anxiety.  There are some notable differences that we can see through these plots.  As the anxiety levels moved from low to high, the range of test scores decreased and the overall average test score increased 5-7 points.