Variance measures how spread out data is. Population variance σ² = Σ(xᵢ−μ)²/N divides by N. Sample variance s² = Σ(xᵢ−x̄)²/(n−1) divides by n−1 (Bessel's correction for unbiased estimation). Standard deviation = √variance, in the same units as the data.
How to Use
Enter your dataset:
- Values: Comma-separated numbers
- Result: Both variances computed
- SD: √variance for each
Population vs Sample
Use population (÷N) when you have ALL the data. Use sample (÷n−1) when your data is a subset. The n−1 correction (Bessel's) makes the sample variance unbiased.
Coefficient of Variation
CV = (σ/μ) × 100%. This standardized measure lets you compare variability of datasets with different units or scales.
Step-by-Step Instructions
- 1Enter data values.
- 2View population and sample variance.
- 3Check standard deviations.
- 4See CV percentage.
- 5Review individual deviations.