Which of the following values can be used for a binomial variable?

• A. 0, 1
• B. 0, 2
• C. 1, 2
• D. -1, 1

Answer: (A)

A binomial variable counts the number of successes in a fixed number of independent trials. Its possible values are nonnegative integers from 0 up to n, where n is the number of trials. This means you can’t have negative counts, and you can’t skip possible counts like 1 when there are at least two trials, since getting exactly one success is a valid outcome.

Among the given options, the pair 0 and 1 fits this pattern: both numbers are nonnegative and can occur (for a single trial, or as part of the range when there are more trials). The pair including 2 would imply that 1 is impossible for that setup, which isn’t true for n ≥ 2. The pair with -1 is invalid because negative counts aren’t possible. Therefore, the values that can be used for a binomial variable are 0 and 1.