Fisher’s iris dataset is the basis for this extended example in the calculation and visualization of correlations. The ggpairs() function gives an impressive coded scatterplot matrix. And an old friend makes a last-minute cameo appearance.

**Update: ** Dirk Eddelbuettel just released tint 0.0.3 (tint is not Tufte) with some nifty examples. I wanted to try it out, so I’ve updated the example using tint and added two margin plots to illustrate the Simpson’s Paradox situation. * Tip from R Bloggers*.