The average is the statistical summary, in one value, of a group of numbers.
There are three main types of averages:
- the mean (the sum or product of the values of a group of numbers divided by how many numbers there are in the group);
- the median (the middle value of a group of numbers);
- the mode or modus (the most common value of a group of numbers).
The most common of these three types is the mean, which can itself be further subdivided into the
- arithmetic mean;
- geometric mean;
- harmonic mean.
However, in common daily usage, the term 'average' often refers to the mean (so instead of arithmetic mean, geometric mean and harmonic mean, the terms arithmetic average, geometric average or harmonic average may also be used), and even more specifically to the arithmetic mean rather than to the geometric mean, harmonic mean, median or mode.