Odds

• The odds against an event E = P(not E) / P(E)
• The odds in favor of an event E = P(E)/P(not E)
• Odds are always given as odds against, unless stated otherwise.

Expected Value

• E= P₁A₁ + P₂A₂ + ... + P_nA_n
• Fair price = expected value + cost to play
• The fair price is the amount to pay for the expected value to be 0.