SOLUTION: The life spans of a computer manufacturer�s hard drives are normally distributed, with a mean of 3 years 6 months and a standard deviation of 9 months. What is the probability of a

Question 1043193: The life spans of a computer manufacturer�s hard drives are normally distributed, with a mean of 3 years 6 months and a standard deviation of 9 months. What is the probability of a randomly selected hard drive from the company lasting between 2 years 3 months and 3 years 3 months? Use the portion of the standard normal table below to help answer the question
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
The life spans of a computer manufacturer�s hard drives are normally distributed, with a mean of 3 years 6 months and a standard deviation of 9 months. What is the probability of a randomly selected hard drive from the company lasting between 2 years 3 months and 3 years 3 months?
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z(2.25) = (2.25-3.5)/(0.75) = -4/3
z(3.25) = (3.25-3.5)/(0.75) = -1/3
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P(2.25< x <3.25) = P(-4/3< z < -1/3) = normalcdf(-4/3,-1/3) = 0.2782
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Cheers,
Stan H.
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