Arithmetic Mean

The arithmetic mean of a set of two or more values is the sum of all the values divided by the number of values. In mathematics and statistics the arithmetic mean is one type of average, or measure of central tendency, but school children are taught to call the arithmetic mean "the average." Because the arithmetic mean is a fundamental measure, it has application in numerous business contexts. Accordingly, the average usually means the arithmetic mean, and an arithmetic mean is generally called an average. For instance, in real estate one key measure of the state of the market is the average number of days on the market for properties for sale. Although this measure would be technically described as the "arithmetic mean of number of days on the market," average days on the market is both simpler to say and widely understood. The term arithmetic mean is infrequently used in place of average, except where technical precision is required.