Explore BrainMass

Explore BrainMass

    Confidence Interval for Mean

    Not what you're looking for? Search our solutions OR ask your own Custom question.

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

    Average electric usage was studied. A previously known population standard deviation was 450 KWH. A sample of 81 houses was studied and found to have a mean of 1858 KWH.

    Find the 95% confidence interval for the true mean.

    © BrainMass Inc. brainmass.com December 15, 2022, 7:50 pm ad1c9bdddf

    Solution Preview

    The formula for a proportion confidence interval is:

    mean ± z * standard deviation / square ...

    Solution Summary

    The 95% confidence interval for the true mean is determined.