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Variance Calculator - Sample & Population
Free variance calculator. Calculate variance and standard deviation for sample or population data. Measure data spread.
Variance Calculator
Calculate variance and standard deviation
Results
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Variance Calculator
Calculate variance and standard deviation to measure how spread out your data is from the mean.
Variance Formulas
Sample: s² = Σ(x-x̄)²/(n-1) | Population: σ² = Σ(x-μ)²/n
Sample variance uses n-1 (Bessel's correction) for unbiased estimation. Population uses n for entire dataset.
Frequently Asked Questions
Sample vs population variance?
Sample: data from a subset, divide by n-1. Population: data from entire group, divide by n. When in doubt, use sample.
What does standard deviation tell us?
~68% of data falls within 1 SD of mean. ~95% within 2 SD. ~99.7% within 3 SD (for normal distributions).
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