6. The office manager of a doctor's office wants to evaluate how long patients are waiting in the waiting room for their appointment. We can assume the wait time is normally distributed with the following statistics: 17.2min 0 7.3min a. At least 80% of patients will have a wait time of what length? (2pts) b. If the office manager takes a random sample of 40 patients, what is the probability that their mean wait time will be more than 15 minutes? (2pts)