In this video we illustrate how to construct a series plot with two series overlayed, even if the scales for the two series are vastly different. The example used here is the same as one we considered in Module 6; it involves plotting the average speed of the winning rider of the Tour de France over time as well as the total distance of the race over time. The speed variable is plotted with respect to the left vertical axis and distance is plotted with respect to the right vertical axis. This example is contained in Mod12Script.R and you should open this script in RStudio and follow along, reading and submitted code as you watch the video. A second example involving plotting multiple profiles of gall bladder volume over time on the same plot is also included in Mod12Script.R. Although the gall bladder example is not included in this video, you should definitely familiarize yourself with the code for that example.
This video is essential viewing.