SOLUTION: An automotive battery company claims its new battery DY-HARD has a mean life of 60 months. Assume the population standard deviation is 9 months. If consumer group selects a random
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Question 873797: An automotive battery company claims its new battery DY-HARD has a mean life of 60 months. Assume the population standard deviation is 9 months. If consumer group selects a random sample of 144 batteries and tests them, what is the probability that the mean life will be more than 62 months? Answer by ewatrrr(24785) (Show Source):
You can put this solution on YOUR website! Population: mean = 60, SD = 9
Sample 144
P(x > 52), z = -8/(9/sqrt(144)) = -8/.75 = -10.6667
P(z > -10.6667) Basically 100%
