SOLUTION: You wish to estimate, with 98% confidence, the proportion of computers that need repairs or have problems by the time they are four years old. The estimate must be accurate within

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Question 322174: You wish to estimate, with 98% confidence, the proportion of computers that need repairs or have problems by the time they are four years old. The estimate must be accurate within 5% of the true proportion.
If no preliminary estimate is available, find the minimum sample size needed.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
You wish to estimate, with 98% confidence, the proportion of computers that need repairs or have problems by the time they are four years old. The estimate must be accurate within 5% of the true proportion.
If no preliminary estimate is available, find the minimum sample size needed.
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n = [z/E]^2*pq
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n = [(invNorm(0.99))/0.05)^2*(1/2)^2 = 2164.7578*(1/4) = 541.18
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n = 542 when rounded up
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Cheers,
Stan H.
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