Some believe that Captain America can run the fastest mile of any person alive. In order to test this theory, Captain America decided to run the mile multiple times and record how long it took him (in seconds) to run each one. He decided to attempt running the mile 40 times and determine his average mile time. Let's assume his true mean mile time was 138 seconds with a standard deviation of 16 seconds. Use this information to find the following probability. What is the probability that his average mile time would be less than 139 seconds