“A Lecturer’s Life.” Dr. Ann Nicholson spends 60% of her work time in her office.

The rest of her work time is spent elsewhere. When Ann is in her office, half the time her light is off (when she is trying to hide from students and get research done). When she is not in her office, she leaves her light on only 5% of the time. 80% of the time she is in her office, Ann is logged onto the computer. Because she sometimes logs onto the computer from home, 10% of the time she is not in her office, she is still logged onto the computer.

1. Construct a Bayesian network to represent the “Lecturer’s Life” scenario just described.

2. Suppose a student checks Dr. Nicholson’s login status and sees that she is logged on. What effect does this have on the student’s belief that Dr. Nicholson’s light is on?