Standard deviation (σ) calculator with mean value & variance online.

**How to use :-**Enter data values delimited with commas (e.g: 3,2,9,4) or spaces (e.g: 3 2 9 4) and press the *Calculate* button.

**HOw to use :-**Enter probability or weight and data number in each row:

It is a Population Sample. Related Probability Calculator Sample Size Calculator Statistics Calculator. Standard deviation in statistics, typically denoted by ,is a measure of variation or dispersion between values in a set of data.

A discrete random variable has a countable number of possible values. The probability of each value of a discrete random variable is between 0 and 1, and the sum of all the probabilities is equal to 1. A continuous random variable takes on all the values in some interval of numbers.