SOLUTION: The mean life of a belted tire is given as 45000 km. The standard deviation is 2250 km. What percent of the tires will have a life that exceeds 47250 km? What percent of the t

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Question 148384: The mean life of a belted tire is given as 45000 km. The standard deviation is 2250 km.
What percent of the tires will have a life that exceeds 47250 km?
What percent of the tires will last longer than 40500 km?

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The mean life of a belted tire is given as 45000 km. The standard deviation is 2250 km.
What percent of the tires will have a life that exceeds 47250 km?
What percent of the tires will last longer than 40500 km?
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Find the z-score for 47250 and for 40500.
z(47250) = (47250-45000)/2250 = 1
P(z> 1 ) = 0.15866...
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z(40500) = (40500-45000)/2250 = -4500/2250 = -2
P(z>-2) = 0.9772499...
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Cheers,
Stan H.