Question 760291: According to a poll conducted by American Express, 35% of people living in the United States use the Internet when planning their vacation.
a. To conduct a follow-up study that would provide 95% confidence that the point estimate is correct to within plus-or-minus 0.04 of the population proportion, how large a sample size is required?
b. To conduct a follow-up study that would provide 99% confidence that the point estimate is correct to within plus-or-minus 0.02 of the population proportion, how large a sample size is required?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! According to a poll conducted by American Express, 35% of people living in the United States use the Internet when planning their vacation.
a. To conduct a follow-up study that would provide 95% confidence that the point estimate is correct to within plus-or-minus 0.04 of the population proportion, how large a sample size is required?
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n = [z/E]^2*pq
n = [1.96/0.04]^2*0.35*0.65 = 547 when rounded up
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b. To conduct a follow-up study that would provide 99% confidence that the point estimate is correct to within plus-or-minus 0.02 of the population proportion, how large a sample size is required?
n = [z/E]^2*pq
n = [2.5758/0.02]0.35*0.65 = 3774 when rounded up
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Cheers,
Stan H.
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