The median of a data set is the middle value of the sorted data. For example, given the data set below which contains items from smallest to greatest:

The median is since it appears in the center position of the sorted data. In the case where there is an even number of elements, the median is calculated as the average of the two middle values.

The mean of a data set is the average of all the values in the data set. It is calculated by adding all the numbers in a list and dividing by the count of numbers in the list.

The mode of a data set is the most commonly occurring value in the data set.