Standard Deviation Calculator
Calculator
Standard Deviation Calculator
About This Calculator
Use the standard deviation calculator when you want faster calculations with a clear method behind every result.
Find variability in datasets by calculating population and sample standard deviation with clear interpretation and scenario comparison.
If your workflow expands, pair this calculator with Z-Score Calculator and Correlation Coefficient Calculator to cross-check assumptions and build a stronger analysis chain.
Formula
Population: σ = sqrt( Σ(x - μ)^2 / N ) | Sample: s = sqrt( Σ(x - x̄)^2 / (n - 1) )
Example Calculation
The worked example below demonstrates how the input fields translate into the final output. Use it as a quick validation pass before entering your own numbers.
- dataset: 2, 4, 4, 4, 5, 5, 7, 9
- type: population
Explanation of Results
Result Interpretation
A standard deviation of 2.00 means values typically sit about 2 units away from the mean, indicating moderate spread in this dataset.
FAQ
Should I use sample or population standard deviation?
Use population when your data includes every observation in the group, and sample when your data is a subset used to estimate the full population.
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See Also
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