The math here is fairly self-evident (I think) but I'm really curious how you'd deploy this in the classroom. Be specific.
BTW: Mr. Follett — concise and correct:
(1) Play clip.
(2) Pass out the photograph, I’d get this by doing a screen grab.
(3) Make other materials available: dollar bills, rulers
(4) Make this info available.
(5) Ask them the shoe size.
(6) Discuss, reflect, justify.
BTW: The application RulerPhone ties into this nicely. More here.
BTW: A much better hook from an audience member at my UC Berkeley presentation than the one I originally concocted: "Which of your classmates could be the killer?"