RE: Probability question: names in hats
March 14, 2016 at 1:54 pm
(This post was last modified: March 14, 2016 at 2:34 pm by Chas.)
Pro tip: It is not about probabilities, it is about combinatorics.
For 2 players (A, B), there is 1 legal order, and 0 ways for B to end up with 'B'. P= 0.
For 3 players (A, B, C), there are 3 legal orders and 1 way for C to end up with 'C'. P= 1/3.
<Recomputing>
Farting around with the combinations, I come up with n! combinations of which n!/2 are legal, and of those (n-2)! end with the last guy stuck.
So the probability P is (n-2)! / (n!/2) -> 2/n(n-1).
For 10 players, that comes out to P = 1/45.
For 2 players (A, B), there is 1 legal order, and 0 ways for B to end up with 'B'. P= 0.
For 3 players (A, B, C), there are 3 legal orders and 1 way for C to end up with 'C'. P= 1/3.
<Recomputing>
Farting around with the combinations, I come up with n! combinations of which n!/2 are legal, and of those (n-2)! end with the last guy stuck.
So the probability P is (n-2)! / (n!/2) -> 2/n(n-1).
For 10 players, that comes out to P = 1/45.
Skepticism is not a position; it is an approach to claims.
Science is not a subject, but a method.
Science is not a subject, but a method.