A public bus company official claims that mean waiting time for bus number 14 throughout peak hours is less than 10 minutes. Karen took bus number 14 throughout peak hours on 18 different occasions. Her mean waiting time was 7.2 minutes with standard deviation of 1.6 minutes. At the 0.01 significance level, test the claim that mean is less than 10 minutes. You might suppose that the time spent waiting for bus 14 is normally distributed.