# Variance (regarding to the arithmetic mean)

## Description

The variance measures how far a set of numbers of n equally likely values is spread out. A small variance indicates that the data tend to be very close to the mean (expected value) and hence to each other, while a high variance indicates that the data are very spread out around the mean and from each other.The arithmetic mean of the values must be precalculated. ( Arithmetic mean is the sum of a collection of numbers divided by the number of numbers in the collection).

Variance is the square of the standard deviation.

## Variables

σ | Variance (dimensionless) |

v | The individual values of a data series (dimensionless) |

X_{i} | The average of the values of the data series (dimensionless) |

n | The number of occurences (dimensionless) |