What is termed as a variable with countable values, such as the number of students?

A discrete variable is characterized by having countable values, meaning it can take specific values that can be counted individually. For example, the number of students in a classroom is a discrete variable because you can count students as whole numbers—1, 2, 3, and so forth—without any fractional values. This type of variable is often associated with counts of items or occurrences where the values cannot be subdivided into finer increments.

Continuous variables, on the other hand, can take on any value within a given range, including fractions or decimals, making them suitable for measurements rather than counts. Nominal variables classify data without a specific numerical order, such as categories like colors or names. Interval variables involve numerical data where the difference between values is meaningful, but lack a true zero point, such as temperature in Celsius. These distinctions clarify why a discrete variable is the correct classification for scenarios involving countable quantities.