Variance

The variance is a measure of spread of a set of data that measures how much the data elements deviate from the mean. Mathematically, the variance is the average of the squares of the difference between each data value x_i and the mean x. (x_1 - x)^2 + (x_2 - x)^2 + ⋯ + (x_n - x)^2/n The variance is the square of the standard deviation σ, so it is usually denoted as σ ^2. σ = sqrt((x_1 - x)^2 + (x_2 - x)^2 + ⋯ + (x_n - x)^2/n) ⇕ σ ^2 = (x_1 - x)^2 + (x_2 - x)^2 + ⋯ + (x_n - x)^2/n The applet below calculates the variance in the data set on the number line. Points can be moved to change the data.