Speaker: Dr. Georges Monette, York University
                 Department of Mathematics and Statistics

Title: An Elliptical Look at Suppression and Other Curiosities

Abstract:  Precisely what is the relationship between Simpson's Paradox and Suppression?  Should we replace the appealing but very misleading Venn Diagram to visualize analysis of variance? Should we replace the term "suppression" with a term that is more general and appropriate? I will ask these questions and more.
We will look for answers in the geometry of the acceptance region -- an ellipse, what else! -- for ordinary-least-squares regression with two predictors.  We will also look at the related geometry of variable space to ask whether we can replace the Venn Diagram with the Pythagoras Diagram. It's hard to see things for which we have no name. And it's hard to see things clearly when we have misleading names or misleading visual metaphors. I plan to propose some naming contests.

Suggested Readings:
Friendly, M., Monette, G. & Fox, J. (2013). Elliptical insights: Understanding statistical methods through elliptical geometry. Statistical Science, 28, 1--39.

Your favorite article on Simpson's paradox and suppression. Failing that, you can try:
Tu, Y.-K., Gunnell, D., & Gilthorpe, M.S. (2008). Simpson's paradox, Lord's paradox, and suppression Effects are the same phenomenon -- the reversal paradox. Emerging Themes in Epidemiology, 5:2.

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