Enter a set of values and choose sample or population to compute standard deviation, variance and the coefficient of variation, comparing dispersion across different units.
类型填 1 为样本标准差，填 2 为总体标准差。
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Sample and population variance | Sample s^2 = sum(x_i - xbar)^2/(n-1); population sigma^2 = sum(x_i - mu)^2/N | ISO 3534-1:2006, Statistics - Vocabulary and symbols |
| Standard deviation | s = sqrt(s^2), in the same unit as the data | ISO 3534-1:2006, Statistics - Vocabulary and symbols |
| Coefficient of variation | CV = s / xbar × 100% | ISO 3534-1:2006, Statistics - Vocabulary and symbols |
| Sample vs. population | Use n - 1 (Bessel correction) for sample data to obtain an unbiased estimate | Cramer H., Mathematical Methods of Statistics (1946) |