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    Confidence Interval and Sample Size Calculations

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    1. Of 300 people waiting lunch at a department store cafeteria, 102 had dessert. What is the confidence associated with a Rao score interval of length .1 (i.e., margin of error .05)?

    2. Calculate the sample size necessary to estimate the proportion of drivers that exceed the spend limit on a stretch of a road between Bakersfield and Los Angeles within a margin of error of .04 with a 99% confidence.

    3. How large a sample is necessary to estimate a politician's approval rating with a margin of error of 3.5% if we want 90%, 95%, and 99% confidence?

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    1. Of 300 people waiting lunch at a department store cafeteria, 102 had dessert. What is the confidence associated with a Rao score interval of length .1 (i.e., margin of error .05)?
    Solution:
    The margin of error, for confidence interval for proportion, is given as follows:
    E=zα2 p1−pn
    Given:
    Proportion of Success, p=102300=0.34
    Sample Size, n=300
    Margin of ...

    Solution Summary

    The solution calculates the confidence interval and sample size of the given problem.

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