Categorized Plots, 2D - Detrended Probability Plot

This categorized plot is constructed in the same way as the standard normal probability plot for the categorized values, except that before the plot is generated, the linear trend is removed. This often "spreads out" the plot, thereby allowing the user to detect patterns of deviations more easily.
For a detailed discussion of Categorized Graphs, see Categorized Graphs in Selected Topics in Graphical Analytic Techniques.