Which of the following is an example of a discrete random variable?

• A. The weight of a randomly chosen apple $(\mathrm{in} \mathrm{grams})$
• B. The amount of time $(\mathrm{in} \mathrm{seconds})$ it takes to run a mile
• C. The number of students present in a classroom
• D. The height of a randomly selected student $(\mathrm{in} \mathrm{centimeters})$

Answer: (C)

Verified step by step guidance

1. Understand the definition of a discrete random variable: it is a variable that can take on countable values, often integers, such as counts of objects or events.
2. Review each option and determine whether the variable can only take specific, separate values (discrete) or any value within a range (continuous).
3. The weight of an apple and the height of a student are measurements that can take any value within a range, so they are continuous random variables.
4. The amount of time to run a mile can also take any value within a range, making it a continuous random variable as well.
5. The number of students present in a classroom can only be whole numbers (0, 1, 2, ...), which makes it a discrete random variable.