<PRE><B>Question 135937</B>
Assuming that the standard deviation of cup amounts dispensed by this machine is 0.42 ounces, what is the minimum sample size needed in order for BIG to be 90% confident that its estimate is within 0.08 ounces of ? 
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Since E = z*sigma/sqrt(n)
n = [z*sigma/E]^2
n = [1.645*0.42/0.08]^2 = 74.58
n = 75 (rounded up)
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Cheers,
Stan H.
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