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Variance Calculator

Find the variance of a data set, for a whole population or a sample.

How it works Report a problem

Variance Pulse

Dynamic Dispersion & Deviation Mapping

About the Variance Calculator

Find the variance of a data set, for a whole population or a sample.

How to use the Variance Calculator

  1. Enter your numbers in Input Stream.
  2. Choose the Data Context: Population or Sample.
  3. Press Calculate.

Formula and method

Population: σ² = Σ(x − μ)² ÷ N. Sample: s² = Σ(x − x̄)² ÷ (n − 1).

Worked example

For 10, 20, 30, 40 the mean is 25. The population variance is 125 and the sample variance is 166.67.

Tips

  • Variance is in squared units. Take the square root for the standard deviation.

Frequently asked questions

Why is sample variance divided by n − 1?
To correct the bias that comes from estimating the population mean using the sample.