Boxplots perform well for comparing groups because it is relatively straightforward to see how the mean and median change over the groups. The following is a display comparing the favorite TV shows selected from a specified set by gender. An experiment was conducted to investigate the effect of a new weed killer to suppress weed germination in onion crops. Both chemicals were tested at high and low concentrations. Here are some box-plots of the results where the whiskers extend to the min and max of the data.
Fewer weeds germinate at higher concentrations of both chemicals.
The results from the control chemical are less variable than the new chemical. High or low concentrations of either chemical have approximately the same effects on weed germination. Department of Statistics, Simon Fraser University.