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wonder8
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From Mathematics: Statistics
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Due on Nov. 08, 2009
Asked on Nov 05, 2009 at 5:38:45PM

Q:

The life span of one species of a maple tree is normally distributed with mean 20 years and standard deviation 2.3 years. If one tree is chosen at random, what is the probability it will live 21 years or longer? What is the probability that the average lifetime of 9 such trees will be 21 years or more?

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Posted on Nov 05, 2009 at 6:26:36PM

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Preview: ... maple tree is normally distributed with mean 20 years and standard deviation 2.3 years. If one ...

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Posted on Nov 05, 2009 at 6:48:45PM

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Preview: ... z > (21 - 20)/2.3] = P(z > 0.4348) = 1 - P(z = 1 - 0.66 ...

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