SOLUTION: Suppose the life of a certain brand of vacuum cleaner is normally distributed with a mean life of 12 years and a standard deviation of 4 years. A vacuum cleaner is randomly chosen.

Question 380341: Suppose the life of a certain brand of vacuum cleaner is normally distributed with a mean life of 12 years and a standard deviation of 4 years. A vacuum cleaner is randomly chosen. Find the probability that is will last between 6 to 12 years.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Suppose the life of a certain brand of vacuum cleaner is normally distributed with a mean life of 12 years and a standard deviation of 4 years. A vacuum cleaner is randomly chosen. Find the probability that is will last between 6 to 12 years.
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z(6) = (6-12)/4 = -3/2
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z(12) = (12-12)/4 = 0
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P(6< x <12) = P(-3/2< z < 0) = 0.4332
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Cheers,
Stan H.
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