TITLE: Reference for elementary and "cool" statistics or financial math
QUESTION [5 upvotes]: I signed up for a Math Mentorship Program (for high school students) this term, but one of the students assigned to me is more interested in Statistics and Finance - something that would help him to do business :-)
The closest I could come up with (using ideas of a friend) is some game theoretic stuff like  price of anarchy  (a related and possibly with much simpler mathematics is  The Economics of Caste and of the Rat Race and Other Woeful Tales  by Akerlof),  Arrow's Impossibility Theorem, and possibly some  Prospect theory.  
Does anyone have any idea about elementary interesting math related to Statistics or Finance?

REPLY [2 votes]: One topic that I would cover is the St. Petersburg Game (or paradox). Daniel Bernoulli's solution is the basis for expected utility theory and the rivalry between himself and his cousin Nicolas just makes it more fun. (The problem is well-suited to a visual description as well.)
Good luck.