You are waiting in line at ORD to go through security. You feel as if you have been waiting for a very long time, and wonder why the airport does not open another lane. Currently, there are 2 open lanes. You remember your waiting time formula from your Service Operations class, and decide to calculate how much the average wait time would be reduced if another lane was open. Fortunately, you arrived early, and have extra time before your flight boards, and so you spend that time making the following measurements.

On average, 40 seconds passes between passenger arrivals to the security checkpoint, with standard deviation 40 seconds. Each passenger takes on average 60 seconds to be screened, with standard deviation 40 seconds.

1. [20 points] What is the average time for a passenger to pass through security, including wait time and screening time? Is this possible that you have been waiting a very long time? Why or why not? 2. [10 points] Would you open another lane? Justify your answer with calculation.

Suppose 60% of the arrivals are PreCheck passengers, and so require reduced security measures. In particular, PreCheck passengers take exactly 25 seconds to be screened (that is, standard deviation equals 0).

3. [30 points] Would you recommend to use one of the two open lanes exclusively for PreCheck passengers and the other of the two open lanes for everyone else? Why or Why not? 4. [10 points] Does your recommendation change if 33% of the arrivals are PreCheck passengers? 5. [20 points] Does your recommendation change if 50% of the arrivals are PreCheck, and the average screening time is 60 seconds with standard deviation 40 seconds for both PreCheck and regular passengers? 6. [10 points] Please formulate two guidelines for when pooling is and is not helpful, based on the answers to questions 3-5 above.