In statistics, the mode of a set of data is the one that occurs most. It is the value x at which its probability mass function takes its maximum value. In other words, it is the value that is most likely to be sampled. A mode of a continuous probability distribution is often considered to be any value x at which its probability density function has a locally maximum value, so any peak is a mode.

The mode of a sample is the element that occurs most often in the collection.

For Example: the mode of the sample

[1, 3, 5, 5, 5, 5, 7, 7, 12, 12, 17] is 5.

Unlike the median and the mean, the mode is not necessarily unique. There might be several different values that occur the same number of times.

Bi Modal and Multimodal

Given the list of data [1, 1, 2, 4, 4] the mode is not unique – the dataset may be said to be bimodal, while a set with more than two modes may be described as multimodal.