# Variance

## Variance

Arithmetic mean of the squares of the deviations of a statistical variable in relationship the arithmetic mean of the distribution.

### Formulas

• In the case of an entire population, the variance is obtained by applying this formula:
$$\dfrac {\sum \left( x_{i}-\mu \right) ^{2}} {N}$$
In which μ represents the arithmetic mean of the distribution and $$N$$ represents the number of data in this population.
• In the case of a sample of this distribution, the variance is obtained by applying this formula:
$$\dfrac {\sum \left( x_{i}-\overline {x}\right) ^{2}} {n-1}$$In which $$\overline {x}$$ represents the mean of the data in the sample and $$n$$ represents the number of data considered.