standard-deviation.md

Standard Deviation

{% hint style="success" %} Standard Deviation is a measure of how spread out numbers are. {% endhint %}

It is the square root of the Variance. It is often more convenient than the variance because it has the same unit as the data points.

Population Standard Deviation, $$\sigma=\sqrt{\frac{1}{n}}\sum_i^n(x_{i}-\mu)^2$$

Sample Standard Deviation, $$\sigma=\sqrt{\frac{1}{1-n}}\sum_i^n(x_{i}-\overline{x})^2$$