A man plays a game in which his probability of winning or losing a dollar is t. Let S" be the man's fortune (that is, the amount he has won or lost) after n independent plays of the game.
(i) Find E[Sn] and Var [Sn].
(ii) Find approximately the probability that after 10,000 plays of the game the change in the man's fortune will be between -50 and 50 dollars.