SOLUTION: Suppose the life of a particular brand of calculator battery is normally distributed with a mean of 80 hours and a standard deviation of 11 hours.
a. what is the probability that
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a. what is the probability that
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Question 874522: Suppose the life of a particular brand of calculator battery is normally distributed with a mean of 80 hours and a standard deviation of 11 hours.
a. what is the probability that a single battery randomly selected from the population will have a life of 75 to 85 hours? .3506
b. what is the probability that 9 randomly sampled batteries from the population will have a mean life of between 75 and 85 hours? Answer by ewatrrr(24785) (Show Source):
You can put this solution on YOUR website! a. z = ± 7/11. .6753-.3247 = .3506 yes
b Sample of 9, s = 11/sqrt(9) = 11/3, z = ± |5/3.6667|= ± 1.3636
.9137 - .0863
