Formula
Population variance averages the squared distance from the mean:
Variance = sum of (value − mean)² / count
The standard-deviation page is a sample and takes the square root.
Assumptions
- The list is the whole population.
- Every value is included in the count.
Worked example
The population 2, 4, 4, 4, 5, 5, 7, 9 has variance 4.
Input definitions
- Population
- The complete set of numbers, separated by commas.
Limitations
This is population variance. A sample would divide by count minus 1.
Questions
Why is this not the square of the other page?
The other page uses a sample divisor. This page uses the full count and does not take a square root.
What is the variance of one number?
Zero. It does not differ from its mean.