<PRE><B>Question 630063</B>
Using the value 850 miles per month as the standard deviation of monthly U.S. rental car mileages from the past year, what is the minimum sample size needed in order for the consumer group to be 90% confident that its estimate is within 175 miles per month of u? 
Carry your intermediate computations to at least three decimal places. 
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n = [z*s/E]^2
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n = [1.645*850/175]^2
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n = 63.83
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n = 64 when rounded up.
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Cheers,
Stan H.
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