Suppose that a category of world class runners are known to run a marathon (26 miles) in an average of 141 minutes with a standard deviation of 13 minutes. Consider 49 of the races. Let

X

= the average of the 49 races.

2. [3/6 Points] DETAILS PREVIOUS ANSWERS ILLOWSKYINTROSTAT1 7.1.064.HW. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Suppose that a category of world class runners are known to run a marathon (26 miles) in an average of 141 minutes with a standard deviation of 13 minutes. Consider 49 of the races. Let X = the average of the 49 races. Part (a) Give the distribution of X. (Round your standard deviation to two decimal places.) X - N V 141 x Part (b) Find the probability that the average of the sample will be between 139 and 142 minutes in these 49 marathons. (Round your answer to four decimal places.) X Part (c) Find the 80th percentile for the average of these 49 marathons. (Round your answer to two decimal places.) * min Part (d) Find the median of the average running times. 141 min