The mean of a data set is the average of all the values in the data set. For example, given the sample data set below:

The mean is calculated by summing together all of the values in the data set and then dividing by the number of values in the set.

Calculating the sum and dividing gives the result:

The mean of this example data set is equal to .

The median of a data set is the middle value of the sorted data.

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