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ZYX Tire Company just developed a new steel- belted radial tire that will be sold at their national chain of stores. Analysis of data shows that the life of tire is distributed as normal with the mean of 62,500 miles and the standard deviation of 5500 miles.
What percentage of the tires can be expected to last between 57000 and 67000 miles?
What percentage of the tires can be expected to last between 67000 and 70000 miles?
What percentage of the tires can be expected to last more than 70000 miles?
Suppose the company plans to give their customers a guarantee mileage so that the company replaces tires free of charge if tires don’t last the stated guarantee mileage. What minimum guarantee mileage should ZYX Company give to their customers so that no more than 4% of the tires will have to be replaced? Show your complete work.