A Classroom Illustration of a Nonintuitive Probability
Richard S. Kleber · Mathematics Teacher Learning and Teaching PK-12 · 1969
Kemeny, Snell, and Thompson1 give as an example of a nonintuitive probability the “matching-birthdays problem.” Briefly stated, the problem is to determine how many people there need be in a room in order that the probability is at least one-half that there are at least two people in the room with the Same birthday. The answer, assuming 365 equally likely birthdays, is much lower than most people would expect.2