Let X denote the waiting time (in minutes) for a customer. An assistant manager claims that μ, the average waiting time of the entire population of customers, is 2 minutes with standard deviation also...

Let X denote the waiting time (in minutes) for a customer. An assistant manager claims that μ, the average waiting time of the entire population of customers, is 2 minutes with standard deviation also 2 minutes. The manager doesn't believe his assistant's claim, so he observes a random sample of 36 custoers. The average waiting time for the 36 customers is 3.2 minutes. What is the probability that the average of 36 customers is 3.2 minutes or more? Do you think that assistant manager's claim that the mean is 2 minutes is correct?