Compute repeatability standard deviation σ_r = R̄/d₂ from the average range of repeated readings using the range method for measurement system analysis (MSA).
重复性标准偏差 = 平均极差 / d₂。
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Repeatability SD (range method) | sigma_r = Rbar / d2, where Rbar is the average range and d2 a sample-size constant | Montgomery DC, Introduction to Statistical Quality Control (7th ed.), Wiley |
| The d2 constant | d2 is tabulated by subgroup size n from the expected range of a normal sample | Montgomery DC, Introduction to Statistical Quality Control (7th ed.) |
| Definition of repeatability | Variation with one operator, one gauge, one part over a short time | AIAG, Measurement Systems Analysis (MSA) Reference Manual, 4th ed. (2010) |
| Combination into GRR | GRR = sqrt(EV^2 + AV^2), where EV is equipment variation | AIAG, Measurement Systems Analysis (MSA) Reference Manual, 4th ed. (2010) |