American Institute of Certified Planners (AICP) Practice Exam

What type of variable takes on a finite number of values, often represented by whole numbers?

1. Continuous variable

2. Nominal variable

3. Discrete variable

4. Dichotomous variable

The correct answer is: Discrete variable

A discrete variable is characterized by its ability to take on a finite number of values, typically expressed as whole numbers. This means that the values are countable and distinct; you cannot have a variable that takes on fractional or decimal values within the context of discrete variables. For example, the number of people in a room or the number of cars in a parking lot are both discrete variables since they can only be whole numbers. In contrast, continuous variables can take on an infinite number of values within a given range, which includes fractions and decimals, making them unsuitable for describing finite whole number outcomes. Nominal variables represent categories without any inherent order, such as colors or types of cuisine, while dichotomous variables only have two possible values, such as yes/no or true/false situations. Thus, the defining characteristic of a discrete variable—being countable and limited to whole numbers—clearly distinguishes it from the other types of variables presented.