Unformatted text preview: d is followed by a blue card. Let X denote the number of cards drawn. Examples: BBBRRB 6 draws, RB 2 draws, RRRB 4 draws, BRRRRRB 7 draws. E(X) = 4.5 (Reduce to a decimal) Solution: Let X R = # draws needed to get a Red card, and X B = # draws needed to get a Blue card. 1
Then X = X R + X B , and so E ( X ) = E ( X R ) + E ( X B ) = 1 1 +
= 3 + 1.5 = 4.5 2
3
3 (b). Suppose that X is a Poisson random variable and P ( X = 1) = P ( X = 2 ) . Determine the value of P( X = 3) = (Exact in terms of e) λ 2e− λ
Solution: From P ( X = 1) = P ( X = 2 ) , we get that λ e −...
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 Spring '13
 Sumner
 Math, Probability, Standard Deviation, Probability theory, Decimal

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