The mode of a set of numbers is defined as the number that appears most frequently in that set. However, when dealing with a set of numbers in which no number repeats, each number occurs with the same frequency, which is once.
Since none of the numbers occurs more than any other, this particular set does not have a mode. In statistical terms, we would say that the mode is undefined or that there is no mode in this scenario.
For example, consider the set of numbers: {2, 3, 5, 7}. Here, each number appears exactly once. Since there is no single number that appears more frequently than the others, we conclude that the set has no mode.