Unformatted text preview: P(X < x ) = 0.23 P(Z < z ) = 0.23 z = 0.74 z = x 0.74 = 25 1325 x x =1306.50 h) What is the account balance, x , such that the probability of a balance being more than it is 0.15? P(X > x ) = 0.15 P(Z > z ) = 0.15 1 P(Z < z ) = 0.15 P(Z < z ) = 0.85 z = 1.04 z = x 1.04 = 25 1325 x x =1351 i) What is the account balance, x , such that the probability of a balance being more than it is 0.5? (Hint: you should be able to do this one without math.) 1325 (the mean) j) Between what 2 central values do 40% of the balances fall? P(x 1 < X < x 2 ) = 0.40 P(z < Z < z ) = 0.40 2P(Z < z )  1 =0.40 P(Z < z ) = 0.70 z = 0.525 z = x Two answers, one for the negative z and one for the positive z. 0.525 = 25 1325 2 x x 2 = 1338.10 0.525 = 25 1325 1 x x 1 = 1311.90...
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 Spring '08
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 Probability, Probability theory, $10, $1310, $1270

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