The average number of miles (in thousands) that a car's tire will function before needing replacement is 66 and the standard deviation is 20. Suppose that 9 randomly selected tires are tested. Round all answers to 4 decimal places where possible and assume a normal distribution. a. What is the distribution of X? X ~ N(:],:]) b. What is the distribution of 5"? :T: w N{:],:]} c. If a randomly selected individual tire is tested, find the probability that the number of miles (in thousands] before it will need replacement is between 61.6 and 68.9. C] d. For the '5' tires tested, find the probability that the average miles [in thousands) before need of replacement is between 61.6 and 63.9. C] e. For part d], is the assumption that the distribution is normal necessary? 0 No0 Yes