Explore BrainMass

Explore BrainMass

    Testing hypotheses about the population 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!

    Fast Service, a chain of automotive tune-up shops, advertises that its personnel can change the oil, replace the oil filter, and lubricate any standard automobile in 15 minutes, on the average. The National Business Bureau received complaints from customers that service takes considerably longer. To check the fast service claim, the Bureau had service done on 21 unmarked cars. The mean service time was 18 minutes and the standard deviation of the sample was 1 minute. Use the .05 significance level to check the reasonableness of the fast service claim.

    © BrainMass Inc. brainmass.com March 6, 2023, 12:44 pm ad1c9bdddf

    Solution Preview

    Solution. Let X be the service time. We can assume that X follows normal distribution, X~N(a, b^2), where a is the mean of X and b is the standard deviation of X. Define Null hypothesis:

    Ho: a=15 (minutes)
    H1: a is not equal 15.

    By the ...

    Solution Summary

    The solution contains detailed explanation of testing whether the population mean is different from a given value.