Plotting points with MATLAB, then marking those above a line of best fit. It is easy to change the code to mark those below the line of best fit. To do this, just change the sign of > to < in the block of code labeled with "comparison" in a comment. Alternatively, you can make it so that both above and below the line of best fit are marked differently. To do this, just copy and paste the comparison code, change the sign, and mess with the color/shape specifications.