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    True Population

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    A marketing firm wants to know the proportion of Sox fans in the Chicago area within a margin of error of 8 percentage points How many people must they survey to be 99% confident that the true population proportion for the Chicago area is within this margin of error? (No prior knowledge regarding proportion is available).

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    https://brainmass.com/statistics/hypothesis-testing/true-population-people-survey-21906

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    See attachment please!

    Analysis:
    The general formula for a confidence interval is
    estimate plus/minus (critical value )(standard deviation of the estimate )
    A 99% confidence interval for proportions has the form

    where N is the sample size and is the sample proportion.
    If the population proportion parameter is p, the margin of error, m, for a 99% confidence interval can be calculated using the formula
    ...

    Solution Summary

    A marketing firm wants to know the proportion of Sox fans in the Chicago area within a margin of error of 8 percentage points How many people must they survey to be 99% confident that the true population proportion for the Chicago area is within this margin of error? (No prior knowledge regarding proportion is available).

    $2.19

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