Variance $σ^{2}$

The example: Calculate variance of values: 1; 2; 3; 4; 5.

A calculation of the variance

x_i (the values are separated by a space):

Variance $σ^{2}$

The variance $σ^{2}$ is the average of the second powers of deviations of the individual values from the arithmetic mean of the values of the statistical set.

$σ^{2} = \frac{⅀_{i = 1}^{n} {(x_{i} - \bar{x})}^{2}}{n}$

$σ^{2}$: variance;
$n$: a number of elements of the statistical set;
$x_{i}$: an element of the statistical set with index i;
$\bar{x}$: a simple arithmetic mean.

Variance is an indicator of variability.

Variance σ 2

Variance $σ^{2}$