The mean () is one of several indices of central tendency that statisticians use to indicate the point on the scale of measures where the population is centered.

The mean is the average of the scores in the population. Numerically, it equals the sum of the scores divided by the number of scores. It is of interest that the mean is the one value which, if substituted for every score in a population, would yield the same sum as the original scores, and hence it would yield the same mean.

This illustration shows a population of 9 persons. It also shows the height of each person as well as the formula and calculations of the mean of the population. As is customary, we have used the Greek letter μ (mu) to represent the mean of a population.