question archive Coin Flipping game: start with $0 and we have unlimited credit
Subject:StatisticsPrice: Bought3
Coin Flipping game: start with $0 and we have unlimited credit. We have a "Head" player and a "Tail" Player. The Head player wins a dollar if the coin is heads and loses a dollar if the coin is tails, and vice versa for the tail player.
(Random Walk)
Consider the "coin flipping game", let Z record the first point in time when some player (either the "Head" player or the "Tail" player) has a lead of $1, and let W record the first point in time when some player has a lead of $2.
Find the least numbers n1 and n2 such that, Prob(Z ≤ n1) > 1/2 and Prob(W ≤ n2) > 1/2. What is E(Z)?