use the given data to find the minimum sample size required to estimate a population proportion or percentageMargin of error: 0.005, confidence level: 99%, p and q unknown  



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Posted on (Answer #1)

Unless the population proportion is very skewed, you can use p=.5 and q=.5

E=.005; confidence level of 99% implies `z_(alpha/2)=2.58` and






Thus to get an error of 1/2% with 99% confidence, you need a sample size of at least 66564.

** You may question the ability to use p=q=.5 As long as the population isn't very divided, the numbers are approximately the same. Using 40% and 60% yields 266256*.24=63901. Even 70%-30% gives 266256*.21=55914, so the use of 50-50 is justified. **


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