SOLUTION: A study of the amount of time it takes a mechanic to rebuild the transmission for a 2005 Chevrolet Cavalier shows that the mean is 8.4 hours and the standard deviation is 1.8 hours
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-> SOLUTION: A study of the amount of time it takes a mechanic to rebuild the transmission for a 2005 Chevrolet Cavalier shows that the mean is 8.4 hours and the standard deviation is 1.8 hours
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Question 1128429: A study of the amount of time it takes a mechanic to rebuild the transmission for a 2005 Chevrolet Cavalier shows that the mean is 8.4 hours and the standard deviation is 1.8 hours. If 40 mechanics are randomly selected, find the probability that their mean rebuild time exceeds 9.1 hours.
You can put this solution on YOUR website! since the sample size(40) is greater than 30, we can use the Normal Distribution
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z-score = (9.1 - 8.4) / 1.8 = 0.3889 is approximately 0.39
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Probalbility(P) (X > 9.1) = 1 -P(X < 9.1)
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P(X < 9.1) is the associated probability for z-score 0.39 in the table of z-scores
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P(X < 9.1) = 0.6517
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P(X > 9.1) = 1 - 0.6517 = 0.3483
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