## What is meant by standard deviation?

Definition: Standard deviation is the measure of dispersion of a set of data from its mean. It measures the absolute variability of a distribution; the higher the dispersion or variability, the greater is the standard deviation and greater will be the magnitude of the deviation of the value from their mean.

## Why is standard deviation used?

Standard deviation is a measure of how spread out a data set is. It’s used in a huge number of applications. In finance, standard deviations of price data are frequently used as a measure of volatility. Standard deviation is a measure of how far away individual measurements tend to be from the mean value of a data set.

**Is standard deviation positive or negative?**

To conclude, the smallest possible value standard deviation can reach is zero. As soon as you have at least two numbers in the data set which are not exactly equal to one another, standard deviation has to be greater than zero – positive. Under no circumstances can standard deviation be negative.

### What happens if the standard deviation is 0?

If the standard deviation is 0 then the variance is 0 and the mean of the squared deviation scores must be 0. The only way that each squared deviation score can be equal to 0 is if all of the scores equal the mean. Thus, when the standard deviation equals 0, all the scores are identical and equal to the mean.