Question 19 For a single-server queuing model (this is the model discussed in the asynch and synch material), in order for the system to be stable, the utilization factor, X/u, has to be: Greater than or equal to 1 Greater than 1 Less than 1 Equal to 1 Question 20 Patients walk-in to a doctor's office, on the average, every 15 minutes with a standard deviation of 15 minutes. The average examination time is 10 minutes with 5 minutes standard deviation. The doctor's utilization is: 133.33% 50% 150% unable to determine based on the data provided 66.67% 8 pts 8 pts