Explore Mean on MathWorld

In statistics, a mean is quantity corresponding to one of possibly several different definitions of the "average" of a set of values, such as the arithmetic, geometric, or harmonic mean. In the absence of additional context, the term "mean" most commnly refers to the arithmetic mean (i.e., the average).

Mean is a middle school-level concept. It is an Advanced Placement Statistics topic and is listed in the California State Standards for Grade 5.


Arithmetic Mean: Arithmetic mean is a synonym for average, i.e., the sum of all values in a list divided by the number of values present.
Geometric Mean: The geometric mean of a set of n numbers is the value obtained by taking the nth root of their product.

Classroom Articles on Probability and Statistics (Up to Middle School Level)

  • Median
  • Problem