What is defined as the item or items that occur most frequently in a data set?

The mode is defined as the item or items that occur most frequently in a data set. In statistical terms, when analyzing a set of values, the mode represents the value that appears with the highest frequency. For example, if you have the data set {2, 4, 4, 5, 6}, the number 4 is the mode because it appears more often than any other number in that set.

In contrast, the median refers to the middle value when a data set is ordered from least to greatest, while the mean is the average of all values in the set, calculated by summing all the values and dividing by the number of values. Inequality does not pertain to a specific value in a data set but rather describes a relationship between different quantities, indicating whether one is less than, greater than, or equal to another. Thus, the mode is the only term among the options that specifically identifies the most frequently occurring item within a data set.