Class summary: Wednesday, 2/26

I continued with combinatorial probability problems. I did several examples of so-called box/ball type problems (which concern samples of balls drawn from a box containing a given number balls of each of two or more different types - say red and blue balls), including the "committee problem" and the "lottery problem". I also discussed the "elevator problem" (6 people get into an elevator in a building with 10 floors; what is the probability that at some floor more than one gets off?), which is mathematically equivalent to the birthday problem, and a variant which asks for the probability that exactly two people get off at the same floor and the others get off at a different floor.

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