CNNBC recently reported that the mean annual cost of auto insurance is 992 dollars. Assume the standard deviation is 249 dollars, and the cost is normally distributed. You take a simple random sample of 13 auto insurance policies. Round your answers to 4 decimal places. a. What is the distribution of X? X - N( b. What is the distribution of D? I - N( c. What is the probability that one randomly selected auto insurance is more than $968? d. a simple random sample of 13 auto insurance policies, find the probability that the average cost is more than $968. e. For part d), is the assumption of normal necessary? ( No Yes