9. To monitor campus security, the campus police ofce is taking a survey of the number of students in a parking lot each 30 minutes of a 24-hour period with the goal of determining when patrols of the lot would serve the most students. If X is the number of students in the lot each period of time, then X is an example of a categorical random variable. a discrete random variable. a continuous random variable. a statistic. PPP'P