Unformatted text preview: them there are more than 16.3 ounces. What are the mean and standard deviation of the amount of soft drink in a randomly selected bottle? 4. (2 points) In a Lone Rock, Iowa, the length of residence of a family in a home is normal with mean 80 months and variance 900. (Negative times are allowed, because they have secretly invented a time machine.) What is the probability that of 12 independent families, living on a certain street of the town, at least three will have lived there more than eight years? 5. (2 points) The random variable X is said to have the double exponential distribution if its density function is f X ( x ) = ce-| x | . (a) Find the value of c that makes this a density. (b) Prove that E [ X 2 n ] = (2 n )! and E [ X 2 n +1 ] = 0 for all n = 1 , 2 , 3 , . . . . 1...
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- Fall '11