Database Reference
In-Depth Information
Figure 7-4. Four different ways of showing variation in a time series
The top-left view is the most straightforward—each team has its own circle in each year. The
top-right view includes reference bands from the minimum to the maximum for each year.
The bottom-left view is a series of circle histograms, wherein the area of each circle is pro-
portional to the number of teams in each bin. The bottom-right view shows a series of box
plots for each year. Each view gives a sense of how much the average number of strikeouts
per nine innings varies from team to team each year.
It may not be important to our message, but if we only showed the average values for each
year, then the assumption many would make is that each team was very close to the points
plotted. Showing variation can be helpful, and there are ways to do so without “hitting the
audience over the head” with all that variation.
