What characterizes a bi-modal distribution?

A bi-modal distribution is characterized by the presence of two distinct peaks or modes in its frequency distribution. This indicates that the data is derived from two different populations or groups that exhibit different characteristics. Each mode represents a set of data values where there is a high frequency of occurrences, typically indicating that there are two underlying processes or phenomena influencing the results.

Therefore, the correct answer highlights that a bi-modal distribution distinctly involves two different populations. Understanding this concept is critical because it allows analysts to recognize more complex data patterns that could imply different causal factors or variations in the dataset that might not be apparent in a unimodal distribution, which would only show one peak.