There are several statistical quantities called means,e.g.,harmonic mean,arithmetic mean,and geometric mean.However,"mean"commonly refers to arithmetic mean that is also called arithmetic average.Arithmetic mean is a mathematical repreesentation of the typical value of a series of number,computed as the sum of all the number in the series divided by the count of all numbers in the series.Arithmetic mean is the balance point if the number are considered as weights on a beam.