In this week's episode Greg and Patrick are honored to visit with Yi Feng, a quantitative methodologist at UCLA, as she helps them understand classification and regression tree analysis. She describes the various ways in which these models can be used, and how these can serve to inform both prediction and explanation. Along the way they also discuss looking pensive, drunken 3-way interactions, Stephen Hawking, parlor tricks, Cartman, validation, dragon boats, anxiety, spam filters, hair loss, audio visualizations, overused tree analogies, rainbows & unicorns, rain in Los Angeles, and Moneyball. Stay in contact with Quantitude! Twitter: @quantitudepod Web page: quantitudepod.org Merch: redbubble.com