Testing of industrial products - Aggregates for construction

Precision values obtained from the cross-testing experiments on the Los Angeles test

Note. For all the tables here, "stragglers" have been included in the calculations, and "outliers" have been excluded.

Table 1. Repeatability and reproducibility
for the European cross-testing experiment
LA units (percentages passing the test sieve)
Level 1Level 2Level 3
Number of laboratories included N 282826
Average X 8.321.637.5
Repeatability standard deviation Sr1 0.2130.4870.572
Reproducibility standard deviation SR1 0.4591.3642.348
Repeatability limit r1 0.61.41.6
Reproducibility limit R1 1.33.86.6
Table 2. Functional relationships for the
European cross-testing experiment
LA units (percentages passing the test sieve)
Functional relationship
Repeatability standard deviation Sr1 = 0.0 + 0.021 X
Reproducibility standard deviation SR1 = 0.0 + 0.060 X
Repeatability limit r1 = 0.0 + 0.06 X
Reproducibility limit R1 = 0.0 + 0.17 X
Table 3. Repeatability and reproducibility standard deviations
for the European cross-testing experiment
expressed as coefficients of variation
Level 1Level 2Level 3
Repeatability coefficient of variation Cr1 2.52.31.5
Reproducibility coefficient of variation CR1 5.56.36.3
Table 4. Sensitivity ratios for the
European cross-testing experiment
Level 2 - Level 1 Level 3 - Level 2Level 3 - Level 1
Repeatability 25.021.247.8
Reproducibility 9.25.912.2
Table 5. Repeatability and reproducibility
for the French cross-testing experiment
LA units (percentages passing the test sieve)
Level 1Level 2Level 3
Number of laboratories included N 333333
Average X 8.121.437.3
Repeatability standard deviation Sr1 0.2950.3340.520
Reproducibility standard deviation SR1 0.6481.6092.140
Repeatability limit r1 0.80.91.5
Reproducibility limit R1 1.84.56.0
Table 6. Functional relationships
for the French cross-testing experiment
LA units (percentages passing the test sieve)
Functional relationship
Repeatability standard deviationSr1 = 0.2 + 0.007 X
Reproducibility standard deviationSR1 = 0.2 + 0.058 X
Repeatability limitr1 = 0.6 + 0.02 X
Reproducibility limitR1 = 0.6 + 0.16 X
Table 7. Repeatability and reproducibility standard deviations
for the French cross-testing experiment
expressed as coefficients of variation
Level 1Level 2Level 3
Repeatability coefficient of variation Cr1 3.61.61.4
Reproducibility coefficient of variation CR1 8.07.55.7
Table 8. Sensitivity ratios
for the French cross-testing experiment
Level 2 - Level 1Level 3 - Level 2Level 3 - Level 1
Repeatability 29.825.748.8
Reproducibility 4.45.913.1