<PRE><B>Question 460554</B>
You want to estimate, with 95% confidence, the population proportion of U.S. adults who drive a car. Your estimate must be accurate within 2% of population proportion. No preliminary estimate is given. Find the minimum sample size needed. Find the minimum sample size needed, using prior study showing that 67% of U.S. adults drive a car. 

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n = [z/E]^2*pq
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n = [1.96/0.02]^2*0.67*0.33 
= 2124 when rounded up
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Cheers,
Stan H.
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