Question 1183574
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From actual road tests with the tires, Hankook Tires estimated that the mean tire mileage is 36,500 miles 
and that the standard deviation is 5000 miles. Data is normally distributed. 
(i)	What percentage of the tires can be expected to last more than 40,000 miles?
(ii)	Assume that Hankook Tires is considering a guarantee that will provide a discount on replacement tires 
if the original tires do not provide the guaranteed mileage. What should the guarantee mileage be 
if the company wants no more than 10% of the tires to be eligible for the discount guarantee?
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I think that the basic assumption made in this problem that the tire mileage is described by the normal distribution 


is  INCORRECT  and  CONTRADICTS  to  COMMON  SENSE,  as well as to the  MATERIAL  SCIENCE.



THEREFORE,  I think,  the problem,  as it is worded,  printed,  posted and presented,  is a  FAKE.



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It is the same as to assume that the age of people is distributed normally, which is, OBVIOUSLY, not a case.