SOLUTION: An automotive repair shop has determined that the average service time on an automobile is 130 minutes with a standard deviation of 26 minutes. A random sample of 40 automotive ser
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Question 359609: An automotive repair shop has determined that the average service time on an automobile is 130 minutes with a standard deviation of 26 minutes. A random sample of 40 automotive services is selected.
a. Compute the standard error of the mean.
b. What is the probability that the sample of 40 automotive services will have a mean service time greater than 136 minutes?
c. Assume the population consists of 400 automotive services. Determine the standard error of the mean.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
An automotive repair shop has determined that the average service time on an automobile is 130 minutes with a standard deviation of 26 minutes. A random sample of 40 automotive services is selected.
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a. Compute the standard error of the mean.
SE = s/sqrt(n) = 26/sqrt(40) = 4.11
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b. What is the probability that the sample of 40 automotive services will have a mean service time greater than 136 minutes?
t(136) = (136-130)/4.11 = 1.4595
P(x-bar >= 136) = P(t >= 1.4595 with df = 39) = 0.0762
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c. Assume the population consists of 400 automotive services. Determine the standard error of the mean.
SE = 26/sqrt(400) = 1.3
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Cheers,
Stan H.
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