Statistical Details for Graphics of Matched Pairs

The primary graph in the Matched Pairs platform is a Tukey mean-difference (Cleveland 1994, p. 130). This graph plots the difference of the two responses on the vertical axis against the mean of the two responses on the horizontal axis. This graph is the same as a scatterplot of the two original variables, but turned 45 degrees. A 45 degree rotation and rescaling turns the original coordinates into a difference and a mean.

Figure 20.6 Example of Transforming to Difference by Mean, Rotated by 45 Degrees