Explore BrainMass

Explore BrainMass

    Confidence interval for the population mean

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    Families USA, a monthly magazine that discusses issues related to health and health costs, surveyed 20 of its subscribers. It found that the annual health insurance premiums for a family with coverage through an employer averaged $10,979. The standard deviation of the sample was $1,000.
    a. Based on this sample information, develop a 90 percent confidence interval for the population mean yearly premium.
    b. How large a sample is needed to find the population mean within $250 at 99 percent confidence?

    © BrainMass Inc. brainmass.com June 3, 2020, 10:25 pm ad1c9bdddf
    https://brainmass.com/statistics/confidence-interval/confidence-interval-for-the-population-mean-229997

    Solution Summary

    This solution finds a 90 percent confidence interval for the population mean and shows how to find the sample size necessary to be 99 percent confident that the margin of error is within a stated bound.

    $2.19

    ADVERTISEMENT