A retail store tracks the number of customers entering each hour and the amount each customer spends. Which of the following correctly classifies the variables?

A retail store tracks the number of customers entering each hour and the amount each customer spends. Which of the following correctly classifies the variables?

• A. Both are discrete
• B. Both are continuous
• C. Customers = discrete; amount spent = continuous
• D. Customers = continuous; amount spent = discrete

Answer: (C)

The key idea is distinguishing discrete versus continuous variables. A discrete variable takes separate, countable values. The number of customers entering each hour is a count, so you can have 0, 1, 2, and so on, but not fractional customers—that makes it discrete. A continuous variable can take on any value within a range. The amount spent by each customer can vary in many small amounts (like 12.99, 12.999, etc.) and, in theory, could take on infinitely many values within a range, so it’s continuous. Therefore, the correct classification is: customers are discrete, and amount spent is continuous.

The key idea is distinguishing discrete versus continuous variables. A discrete variable takes separate, countable values. The number of customers entering each hour is a count, so you can have 0, 1, 2, and so on, but not fractional customers—that makes it discrete. A continuous variable can take on any value within a range. The amount spent by each customer can vary in many small amounts (like 12.99, 12.999, etc.) and, in theory, could take on infinitely many values within a range, so it’s continuous. Therefore, the correct classification is: customers are discrete, and amount spent is continuous.