SOLUTION: help help help The shelf life of a battery produced by one major company is known to be normally distributed, with a mean life of 3.9 years and a standard deviation of 0.3 yea

Question 867591: help help help

The shelf life of a battery produced by one major company is known to be normally distributed, with a mean life of 3.9 years and a standard deviation of 0.3 years. What is the probability that a randomly chosen battery will last between 3.5 and 4.1 years?
thank you
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
The shelf life of a battery produced by one major company is known to be normally distributed, with a mean life of 3.9 years and a standard deviation of 0.3 years. What is the probability that a randomly chosen battery will last between 3.5 and 4.1 years?
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z(3.5) = (3.5-3.9)/0.3 = -0.5/0.3 = -1 2/3
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z(4.1) = (4.1-3.9)/0.3 = 0.2/0.3 = 2/3
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P(3.5 < x < 4.1) = P(-1 2/3 < z < 2/3) = normalcdf(-5/3,2/3) = 0.6997
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Cheers,
Stan H.
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