American Institute of Certified Planners (AICP) Practice Exam

A number calculated on population data that qualifies a characteristic of the population is a?

1. Dependent variable

2. Variable

3. Statistic

4. Parameter

The correct answer is: Parameter

In the context of statistical analysis, when referring to a number calculated on population data that encapsulates a characteristic of the entire population, the term "parameter" is used. A parameter is a descriptive measure that summarizes the entire population’s attributes, such as the population mean or the population proportion. For example, if you were to summarize the average income of an entire city, that average would be a parameter of the city's population. In contrast, the other terms represent different concepts within statistics. A dependent variable is an outcome that is measured in an experiment, often influenced by an independent variable. A statistic is also a summary measure, but it refers specifically to a characteristic derived from a sample rather than the entire population. Meanwhile, a variable simply refers to any characteristic, trait, or attribute that can vary among individuals or observations. Thus, "parameter" is the correct term to use when summing up a characteristic of the population itself.