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    Statistics - Random sample and confidence interval

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    You are given the sample mean and the sample deviation, Use this information to construct the 90% and 95% confidence intervals for the population mean. Which interval is wider?

    A random sample of 38 gas grills has a mean price of $638.20 and a standard deviation of $59.80.

    a)The 90% confidence interval is __,__ (round to two decimal places)

    b)The 95% confidence interval is __,__ (round to two decimal places)

    c)Which interval is wider? The 90% or 95% confidence interval? (choose one)

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    Solution Preview

    n = 38, x-bar = 638.20, s = 59.80

    SE = s/sqrt n = 59.80/sqrt 38 = 9.7008

    (a) z = 1.645

    The ...

    Solution Summary

    The random sample and confidence intervals are examined. A complete, neat and step-by-step solution is provided.