Compute u_A = s/√n from sample standard deviation and the number of independent measurements (statistical evaluation).
输入样本标准差 s 与测量次数 n，求 A 类标准不确定度。
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Type A standard uncertainty | u_A = s / sqrt(n), the experimental standard deviation of the mean | JCGM 100:2008, Guide to the Expression of Uncertainty in Measurement (GUM) |
| Experimental standard deviation | s = sqrt( sum(x_i - xbar)^2/(n-1) ) from n independent observations | JCGM 100:2008, Guide to the Expression of Uncertainty in Measurement (GUM) |
| Degrees of freedom | nu = n - 1, used to fix the coverage factor and confidence level | JCGM 100:2008, Guide to the Expression of Uncertainty in Measurement (GUM) |
| Combining with Type B | u_c = sqrt(u_A^2 + u_B^2), combining both types in quadrature | JCGM 100:2008, Guide to the Expression of Uncertainty in Measurement (GUM) |