The mean is a term in statistics. The mean is a method of determining the central tendency, the average, of a set of data, although being the most common method for doing this it is generally simply referred to as 'the average'. The mean is the sum of a set of numbers divided by how many numbers are in the set.
To find the mean, the numbers are added and divided by the quantity of numbers in the group. For example: to find the mean of 3, 4, 6, and 7, we add them together: 3 + 4 + 6 + 7 = 20. Then we divide them by the quantity of numbers in the group, which is 4. 20 / 4 = 5.
Most spreadsheet programs and computer languages consider average to be the mean, but there are three common types of average. Often the median is far from the mean, when values are skewed in one direction.