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3. One coin is said to be fair if P (Head) = P (Tail). otherwise it is said to be unfair. Now we have a unfair coin A where P(Head) = 0.4. To solve the following problems: a) Let X as one random variable defined by X( \"Head" )= 1 and X( \"Tail" ) = 1. Compute the expected value and variance of X. If we toss the coin A for 3 times sequentially, b) what are sample space, simple events for this experiment ? How many compound events ? c) Let Y as the number of Heads. Compute the expected value and variance of Y. d) What is the probability of the event \"The number of occurrence of Head is no less than the number of occurrence of Tail" ? (Hint: you can use tree diagram or combinatorial rule.) e) What is the probability of the event "The number of Heads is less than the number of Tails if we observe the first occurrence is Tail"