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

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

• A. The number of cups of coffee served at Saxby's between 4pm and 6pm today
• B. The temperature in Celsius
• C. The height of students in a class
• D. The weight of a single apple

Answer: (A)

A discrete random variable is one that can take on a countable number of distinct values, often resulting from a counting process. In this case, the number of cups of coffee served at Saxby's between 4 pm and 6 pm today exemplifies a discrete random variable because you can count the cups—there are 0, 1, 2, 3, etc. cups served, and it is impossible to serve a non-integer number of cups. In contrast, other examples among the options represent continuous random variables. Temperature in Celsius, for instance, can take any value within a range and can be measured with great precision, indicating an infinite number of possible outcomes between any two values. Similarly, the height of students and the weight of a single apple can assume a continuous range of values and do not limit to whole numbers—they can be expressed in decimal points or fractions (e.g., 150.5 cm tall or 0.75 kg in weight), making them continuous rather than discrete. Thus, the first option stands as the only example of a discrete random variable in this scenario.

A discrete random variable is one that can take on a countable number of distinct values, often resulting from a counting process. In this case, the number of cups of coffee served at Saxby's between 4 pm and 6 pm today exemplifies a discrete random variable because you can count the cups—there are 0, 1, 2, 3, etc. cups served, and it is impossible to serve a non-integer number of cups.

In contrast, other examples among the options represent continuous random variables. Temperature in Celsius, for instance, can take any value within a range and can be measured with great precision, indicating an infinite number of possible outcomes between any two values. Similarly, the height of students and the weight of a single apple can assume a continuous range of values and do not limit to whole numbers—they can be expressed in decimal points or fractions (e.g., 150.5 cm tall or 0.75 kg in weight), making them continuous rather than discrete. Thus, the first option stands as the only example of a discrete random variable in this scenario.