SOLUTION: A medical reseracher wishes to determine the percentage of females who take vitamins. He wishes to be 99% confident that the estimate is within 4% of the true proportion. How large

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Question 308686: A medical reseracher wishes to determine the percentage of females who take vitamins. He wishes to be 99% confident that the estimate is within 4% of the true proportion. How large should the sample size be?
Answer by stanbon(75887) (Show Source):
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A medical researcher wishes to determine the percentage of females who take vitamins. He wishes to be 99% confident that the estimate is within 4% of the true proportion. How large should the sample size be?
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z(99.5) = 2.5758
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Formula:
n = [z/E]^2(pq)
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p= 0.5 is the least biased estimate of "p", so use it:
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n = [2.5758/0.04]^2(0.5*0.5) = 1036.7
Round up to n = 1037
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Cheers,
Stan H.
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