mean (M), arithmetic

the sum of scores divided by the number of scores. So the mean of 2 and 4 is the sum of 6 divided by 2 scores which gives a mean of 3.00. The mean is the central point in a set of scores in that the sum of absolute deviations (i.e. ignoring the negative signs) of scores above the mean (4 – 3.00 = 1.00) is equal to the sum of absolute deviations of scores below the mean (2 – 3.00 =- 1.00). The mean is sometimes called the arithmetic mean to distinguish it from other forms of mean such as the harmonic mean or geometric mean. Because it is the most common form of mean it is usually simply called the mean. It is sometimes abbreviated as M with or without a bar over it.