# Question: the waiting time at a certain bank is approximately normally...

###### Question details

The waiting time at a certain bank is approximately normally distributed with a mean of 3.7 min and a standard deviation of 1.4 min.

1. Find the probability that a randomly selected customer has to wait less than 2.0 min.

2. What is the waiting time T such that the probability that a customer waits longer than T is only 0.05?

3. Find the probability that a randomly selected customer has to wait more than 6.0 min.

4. If a random sample of 2 customers is selected, find the probability that the average waiting time is more than 6.0 min.

5. If a random sample of 4 customers is selected, find the probability that the average waiting time is more than 6.0 min.

6. If a random sample of 10 customers is selected, find the probability that the average waiting time is more than 6.0 min.