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OF I RODADILIT POINTS) A.1 (1 Point) Consider a random variable A with sample space SA = {1, 2, 3} and a random variable B with sample space SB = {1, 2}. Based on the the Law of Total Probability, define marginal probability P(B = 2) in terms of conditional probabilities and in terms of joint probabilities (0.5 points). Explain in one or two sentences what is the meaning of this law (0.5 points)