Which of the following best defines a binary variable?

• A. A variable that can take any value within a given range
• B. A variable that can take only two possible values, such as $0$ and $1$
• C. A variable that measures the time until an event occurs
• D. A variable that represents categories with more than two levels

Answer: (B)

Verified step by step guidance

1. Understand that a binary variable is a type of categorical variable with exactly two possible values or categories.
2. Recognize that these two values often represent two distinct states, such as 0 and 1, yes and no, or true and false.
3. Contrast this with other types of variables: continuous variables can take any value within a range, time-to-event variables measure duration until an event, and categorical variables with more than two levels have multiple categories.
4. Therefore, the defining characteristic of a binary variable is its limitation to only two possible values.
5. Summarize that the best definition of a binary variable is one that can take only two possible values, such as 0 and 1.