Standard Deviation Calculator
Calculate sample and population standard deviation, variance, mean and standard error from any list of numbers.
Separate values with commas, spaces or new lines
Standard deviation (σ)
5.24
Détail
- Variance (σ²)
- 27.43
- Mean
- 18
- Standard error
- 1.85
- Count
- 8
- Note
Dernière mise à jour:
FAQ
Sample or population standard deviation?
If your numbers are a sample from a larger group, divide by n−1 (Bessel's correction) to estimate the population spread. Only use n when you have every member of the group.
What does 1, 2 and 3 sigma mean?
In normally distributed data, ±1σ covers ~68% of values, ±2σ ~95% and ±3σ ~99.7% — the empirical rule behind Six Sigma quality control.
What is a good standard deviation?
There is no universal good — SD scales with your data. Compare spread across datasets with the coefficient of variation: SD ÷ mean.
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