Research Article
Quantifying Repeatability Reproducibility Sources of Error and Capacity of a Measurement: Demonstrated Using Laboratory Soil Plasticity Tests
Table 7
Repeatability and reproducibility results reported in ASTM D4318 and determined by two-way ANOVA-based analysis for the various laboratory tests.
| Parameters | Liquid limit | Plastic limit | Bar linear shrinkage | Casagrande cup | Fall cone | ASTM rollerb | Fall cone |
| Repeatability and reproducibility (R&R) reported in ASTM D4318a | Single-operator standard deviation (%) (within-laboratory repeatability) | 0.5 | NA | 0.3 | NA | NA | Multilaboratory standard deviation (%) (between-laboratory reproducibility) | 1.3 | 0.9 |
| Two-way ANOVA-based R&R Analysis Results | (%) | 0.6 | 0.5 | 0.4 | NA | 0.6 | | 30 | 30 | 24 | 30 | 95% confidence interval (%) | 0.5–0.8 | 0.4–0.6 | 0.3–0.5 | 0.5–0.9 | (%) | 1.7 | 0.5 | 0.6 | 0.7 | | 6 | 3 | 5 | 3 | 95% confidence interval (%) | 1.1–3.8 | 0.3–1.7 | 0.4–1.5 | 0.4–2.7 | (%) | 1.8 | 0.7 | 0.7 | 1.0 | | 8 | 10 | 11 | 10 | 95% confidence interval (%) | 1.3–3.5 | 0.5–1.1 | 0.5–1.2 | 0.7–1.7 | Fraction of due to | 11 | 50 | 27 | 43 | Fraction of due to | 89 | 50 | 73 | 57 |
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aThe R&R analysis was conducted on a USCS: ML soil. bThe ASTM PL test was conducted on four samples, because the 0% bentonite sample was nonplastic.
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