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| Question 616221:  A government survey conducted to estimate the mean price of houses in a metropolitan area is designed to have a margin of error of $10,000.  Pilot studies suggest that the population standard deviation is $70,000.  Estimate the minimum sample size needed to estimate the population mean with the stated accuracy.
 Answer by stanbon(75887)
      (Show Source): 
You can put this solution on YOUR website! A government survey conducted to estimate the mean price of houses in a metropolitan area is designed to have a margin of error of $10,000. Pilot studies suggest that the population standard deviation is $70,000. Estimate the minimum sample size needed to estimate the population mean with the stated accuracy. -----
 ME = z*s/sqrt(n)
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 n = [z*s/ME]^2
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 n = [1.96*70000/10000]^2 = [1.96*7]^2 = 189 when rounded up
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 Note: I assumed you wanted 95 degree confidence.
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 Cheers,
 Stan H.
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