What is the mathematical term for the number that appears most frequently in a data set?

The number that appears most frequently in a data set is referred to as the mode. In statistical terms, the mode is the value that occurs with the highest frequency within a given set of numbers. For example, in the data set {1, 2, 2, 3, 4}, the mode is 2 since it appears more often than any other number in that set.

The other terms have distinct meanings: the median represents the middle value when a data set is ordered from least to greatest; the mean is the arithmetic average of the values; and the range measures the difference between the largest and smallest values in the data set. Each of these terms serves a different purpose in data analysis, but when identifying the most frequently occurring value, the mode is the correct and relevant term.