Since the inception of the discussion sessions, of the students enrolled in the course regularly attended the sessions, and the other did not. Students regularly attending the sessions have performed better than those not regularly attending. In particular, of the students regularly attending the sessions received a grade of "B" or higher in the course, while only of the students not regularly attending the sessions received a grade of "B" or higher in the course. Let denote the event that a randomly chosen student (enrolled in the course) regularly attended the discussion sessions, and let denote the event that a randomly chosen student did not regularly attend the discussion sessions. Let denote the event that a randomly chosen student received a grade of "B" or higher in the course, and let denote the event that a randomly chosen student did not receive a grade of "B" or higher in the course.