Suppose that the talk time on a fully charged iPhone is approximately normally distributed with mean 7 hours and standard deviation 0.8 hour. What is the probability that a random sample of 16 fully...

Suppose that the talk time on a fully charged iPhone is approximately normally distributed with mean 7 hours and standard deviation 0.8 hour. What is the probability that a random sample of 16 fully charged iPhones results in a mean talk time of less than 6 hours?