sample mean

an estimate of the average of a group of numbers.

One of the key attributes of any group of scores is its mean. This is an estimate of the center of the distribution- the "central tendency." The symbol for a sample mean is ("x-bar").

A group of scores is a "sample" if it is a selection of a very large or infinite pool of scores. For instance, the height of all men on the local hockey team is a sample of the height of all men in the world. The cost of a cup of coffee in three cafes is a sample of the cost of all cups of coffee, everywhere. (That is a sample with an N of 3, because it has three scores).

The sample mean is calculated by adding all scores and dividing by N, the number of scores.