What is the probability of a world series ending after 4 games? After 5 games? 6 games? 7 games?

Assume that each team has equal probability of winning each game, regardless of who has won the previous games.

(For the baseball-challenged, the World Series ends after one team has won 4 games. Ties are not possible.)

After 4 games = 2•(0.5^4) = 0.125
After 5 games = 8•(0.5^5) = 0.25
After 6 games = 20•(0.5^6) = 0.3125
After 7 games = 40•(0.5^7) = 0.3125

Posted by Erik O. on 2004-06-08 12:26:31