Standard Deviation

Properties2

Type	Concept
Note created	Feb 17, 2025

The standard deviation is the average amount of variability of a population or a sample. It is a measure of dispersion: low standard deviation means that values are located closer to the mean, while a larger standard deviation means that there is a higher dispersion.

It is usually represented using $\sigma$ or $S$ and can be computed using:

$$\sigma =\sqrt{\frac{\sum (x_i-\mu {)}^2}{N}}$$

Being $N$ the size of the population, $x_i$ each sample of the population and $\mu$ the mean of the population.