4. One particular brand of tires lasts for an average of 52000 miles with a standard deviation of approximately 6000 miles. The distribution of tire lifespan is normally distributed. a. If the tire manufacture guarantees a full refund on tires for 45,000 miles, what percentage of tires will the company expect to replace? b. If the tire manufacturer only wants to refund 3% (or less) of the tires it makes, how long should the guarantee period be (to the nearest mile). solutions for week 6 for the correct values