Average

Average is a term in mathematics used to measure the 'central tendency' or 'expected value' of a data set; in conversational terms, it would be expected to be a value somewhere in the middle of the data.

There are various descriptive statistics that can be chosen as a measurement of the this central tendency, such as the mode, the median and the mean, this latter coming in a variety of forms: harmonic mean, geometric mean and arithmetic mean. The arithmetic mean is the most common type of mean, and it is the one that most people would generally take as the average.

Thus one way of defining the average of a set of data would be:

• the sum of all the values divided by the number of items in the data set.

Please see the table of mathematical symbols for explanations of the symbols used.

Example of calculation

To calculate the average of 3, 5, and 7:

The total of the data is ,math> 3 + 5 + 7 = 15 </math>

There are 3 items in the data set. 

So the average is <math>15 \div 3=5</math>.