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    Confidence Interval Estimates for Means

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    A simple random sample of 25 has been collected from a normally distributed population for which it is known that ? = 17.0. The sample mean has been calculated as 342.0, and the sample standard deviation is s = 14.9. Construct and interpret the 95% and 99% confidence intervals for the population mean.

    NOTE: Please use an Excel spreadsheet for response. Please do not just
    provide the answer but show in complete detail how you arrived at the
    answer, step-by-step, from the beginning to the end of the solution.


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    Solution Preview

    Please see the attachments.

    95% confidence interval
    Since the population standard deviation is known, we can use the normal distribution for the construction of CI.
    The confidence interval is given by
    Given that = 342.0, σ = 17.0, n = 25, = 1.96
    Hence the required confidence interval is given by,
    = (335.336, 348.664)
    Confidence Interval Estimate for ...

    Solution Summary

    The solution provides step by step method for the calculation of confidence interval for population mean. Formula for the calculation and Interpretations of the results are also included. Interactive excel sheet is included. The user can edit the inputs and obtain the complete results for a new set of data.