SOLUTION: Scores on a certain test are normally distributed with a variance of 22. A researcher wishes to estimate the mean score achieved by all adults on the test. Find the sample size

Question 1108906: Scores on a certain test are normally distributed with a variance of 22. A researcher wishes to estimate the mean score achieved by all adults on the test.
Find the sample size needed to assure with 95% confidence that the sample mean will not differ from the population mean by more than 2 units.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Scores on a certain test are normally distributed with a variance of 22. A researcher wishes to estimate the mean score achieved by all adults on the test.
Find the sample size needed to assure with 95% confidence that the sample mean will not differ from the population mean by more than 2 units.
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Since ME = z*s/sqrt(n), n = [z*s/ME]^2
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Ans: n = [1.96*22/2]^2 = 21.56 ~ 22 when rounded up
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Cheers,
Stan H.
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