Suppose that the time T between text messages sent from your cell phone is governed by the exponential distribution with mean m = 15 minutes and...

Suppose that the time T between text messages sent from your cell phone is governed by the exponential distribution with mean m = 15 minutes and standard deviation s = 20 minutes. You record the next 75 times between sent text messages. What is the probability that their average time exceeds 17 minutes Apply the Central Limit Theorem.