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 1171768: 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 is less than 8.9 hours.
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
z=(x bar-mean)/sigma/sqrt(n)
< (8.9-8.4)/1.8/sqrt(40)
< 0.5*sqrt(40)/1.8
< 1.756
probability is 0.9605
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