Assume that a random variable is normally distributed with a mean of 1,400 and a variance of 304. Complete parts a through c below. a. What is the probability that a randomly selected value will be greater than 1,420? The probability is 0.1257 . (Round to four decimal places as needed.) b. What is the probability that a randomly selected value will be less than 1,387? The probability is D. (Round to four decimal places as needed.) b. Calculate the mean and standard deviation of the en route delays. Find the mean. Mean = 0.764 (Round to three decimal places as needed.) Find the standard deviation. Standard deviation = 0.827 (Round to three decimal places as needed.) c. Assume the population has an exponential distribution. Determine the probability that this exponential random variable will be smaller than its mean. P(x