# SOLUTION: A 20-minute Oil and Lube service claims that their average service time is no more than 20 minutes. A random sample of 40 service times was collected, and the sample mean was found

Algebra ->  Probability-and-statistics -> SOLUTION: A 20-minute Oil and Lube service claims that their average service time is no more than 20 minutes. A random sample of 40 service times was collected, and the sample mean was found      Log On

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 Click here to see ALL problems on Probability-and-statistics Question 386229: A 20-minute Oil and Lube service claims that their average service time is no more than 20 minutes. A random sample of 40 service times was collected, and the sample mean was found to be 21.3 minutes, with a sample standard deviation of 5.5 minutes. Is there evidence to reject the claim at the alpha = 0.05 level? Perform an appropriate hypothesis test, showing the necessary calculations and/or explaining the process used to obtain the results.Answer by stanbon(60771)   (Show Source): You can put this solution on YOUR website!A 20-minute Oil and Lube service claims that their average service time is no more than 20 minutes. --------------------------------- A random sample of 40 service times was collected, and the sample mean was found to be 21.3 minutes, with a sample standard deviation of 5.5 minutes. ------------------------- Is there evidence to reject the claim at the alpha = 0.05 level? Perform an appropriate hypothesis test, showing the necessary calculations and/or explaining the process used to obtain the results. ---------------------------- Ho: u <= 20 min (claim) Ha: u > 20 min -------------------- test statistic: t(21.3) = (21.3-20)/[5.5/sqrt(40)] = 1.4949 ------ p-value = P(t > 1.4949 when df=39) = 0.0715 --- Since the p-value is greater than 5%, fail to reject Ho. Conclusion: The test results support the claim. ================ Cheers, Stan H.