Mixed Strategy Equilibrium

Mixed Strategy Equilibrium for a player is a probability distribution over some of her strategies. The strategy we have studied so far, i.e., taking some action for sure, is called a pure-strategy. When the outcome of the game is uncertain, we assume that each player maximizes expected value of her payoff. If a player takes both “Heads” and “Tails” with positive probability, he must be indifferent between these two pure strategies, i.e., the expected payoff derived by choosing Heads must be equal to that by choosing Tails.