What is standard deviation?

A measure of spread. σ = √(Σ(x−μ)²/n) for population; s = √(Σ(x−x̄)²/(n−1)) for sample.

Online Standard Deviation Calculator

Calculate sample or population standard deviation and variance from a list of numbers.

Numbers (comma or space separated)Population (not sample)

What is standard deviation?: A measure of spread. σ = √(Σ(x−μ)²/n) for population; s = √(Σ(x−x̄)²/(n−1)) for sample.

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Calculate C(n,r) — the number of ways to choose r items from n without order. Uses n!/(r!(n-r)!).

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Calculate the number of ways to choose r items from n with repetition allowed. Formula: C(n+r-1, r).

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Count how many permutations of n objects are even (expressible as an even number of swaps). For n ≥ 2, equals n!/2.