Question 632936: A researcher is interested in estimating the noise levels in decibels at area urban hospitals. She wants to be 90% confident that her estimate is correct. If the standard deviation is 5.07, how large a sample is needed to get the desired information to be accurate within 0.66 decibels? Show all work.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A researcher is interested in estimating the noise levels in decibels at area urban hospitals. She wants to be 90% confident that her estimate is correct. If the standard deviation is 5.07, how large a sample is needed to get the desired information to be accurate within 0.66 decibels?
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E = z*s/sqrt(n)
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So, n = [z*s/E)^2
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n = [1.645*5.07/0.66]^2
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n = 160 when rounded up
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Cheers,
Stan H.
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