the amount of time that customer spends waiting at an airport check in

Question

The amount of time that customer spends waiting at an airport check-in counter is a random variable with mean 8.4 minutes and standard deviation 1.3 minutes.Suppose that a random sample of n= 45 customers is observed. Find the probability that the average time waiting in line for these customers is (a) Less than 10 minutes (b) Between 5 and 10 minutes (c) Less than 6 minutes Round your answers to one decimal place (e.g. 98.7). (a) The probability is (b) The probability is (c) The probability is