Investigations 9-11: Using a Box and Whisker Plot to Compare Data Sets

In addition to providing us with insight into the results for a single variable, we can use box and whisker plots and dot plots to examine differences between variables and differences within a single variable when we can divide that variable into different groups.

Investigation 9. Figure 2 shows box and whisker plots and dot plots for all six colors of M&Ms included in Table 2 (note: even with jittering, you will not be able to see all 30 samples in these dot plots). Based on these plots, where do you see similarities and where do you see differences in the distribution of M&Ms? What do these similarities and differences suggest to you? For those distributions that do not appear symmetrical, suggest one or more reasons for the lack of symmetry. What do the relative positions of the data for brown and for green M&Ms suggest about their relative abundance in 1.69-oz packages of plain M&Ms?

Investigation 10. Figure 3 shows box and whisker plots and dot plots for yellow M&Ms grouped by the store where the packages of M&Ms were purchased. Based on these plots, where do you see similarities and where do you see differences in the distribution of yellow M&Ms? What do these similarities and differences suggest to you? In what ways might this data be reassuring to us? Give an example of a result that might suggest we look more closely at our data.

Investigation 11. Draw a box and whisker plot and an accompanying dot plot for the total number of M&Ms. Compare your plots to those in Figure 2 and discuss any similarities and differences.