Sportscasters misunderstanding probability
March Madness is upon us, so it's time for more "sportscasters misunderstanding probability" fun. Here is one I hear a lot:
Let's say that every single year, one of the four 14-seeds beats one of the four 3-seeds. Pundits will say, "Well, because one of the 14-seeds always wins, you should pick one to upset a 3."
No: unless you have some special knowledge as to which 14-seed will win, you should pick all four 3s. Then, you will get 3 of the 4 games right. But if you pick (at random) a 14-seed to win, one time out of four you will get four right, but three times out of four you will get two wrong. That's an expected 1 and 1/2 wrong, as opposed to a certain one wrong by picking all the 3s.
Let's say that every single year, one of the four 14-seeds beats one of the four 3-seeds. Pundits will say, "Well, because one of the 14-seeds always wins, you should pick one to upset a 3."
No: unless you have some special knowledge as to which 14-seed will win, you should pick all four 3s. Then, you will get 3 of the 4 games right. But if you pick (at random) a 14-seed to win, one time out of four you will get four right, but three times out of four you will get two wrong. That's an expected 1 and 1/2 wrong, as opposed to a certain one wrong by picking all the 3s.
This should be a TV show: "America's Least Probable Sportscasters"
ReplyDeleteOne of the announcers on CBS just mentioned how, "When you fill out your bracket, you always have to figure out which 12 will beat a 5."
ReplyDeleteIt's like a ratings difference in chess. If your rating is 200 points higher than mine and we play a 6 game match you should bet on a score of 5 to 1.
ReplyDeleteBut one isn't betting on *how many* 12s will advance! You have to *pick one of them*. And that means you should pick none.
DeleteI am pointing out his confusion. You should expect a one in a million event to happen once in a million events, not zero, but in any particular instance you should bet against it.
DeleteI always bet for you to beat MF, for exactly this reason, and exactly these odds.
Yes, got it.
Delete