Standard Deviation Calculator
Standard Deviation
Enter comma-separated numbers (e.g. 5, 10, 15, 20, 25)
Formula
σ = √(Σ(xi - μ)² / N) | s = √(Σ(xi - x̄)² / (n-1))
Frequently Asked Questions
What is standard deviation?
Standard deviation measures how spread out numbers are from the mean. A low standard deviation means data points are close to the mean; a high standard deviation means they are spread out over a wider range.
What is the difference between population and sample standard deviation?
Population SD (σ) divides by N (total count). Sample SD (s) divides by N-1 (Bessel's correction) to account for estimating from a sample. Use sample SD when your data is a subset of a larger population.
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