Testing of industrial products - Aggregates for construction

Precision values obtained from the cross-testing experiment on the Schlagversuch

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

Table 1. Repeatability and reproducibility.
		Level 1	Level 2	Level 3
Number of laboratories included	N	14	15	16
Average	X	11.0	21.6	27.7
Repeatability standard deviation	S_r1	0.177	0.223	0.255
Reproducibility standard deviation	S_R1	0.408	0.606	1.225
Critical range	W_c	1.0	1.2	1.5
Repeatability limit	r₁	0.5	0.6	0.7
Reproducibility limit	R₁	1.1	1.7	3.4

Table 2. Functional relationships.
	Functional relationship
Repeatability standard deviation	S_r1 = 0.125 + 0.0046 X
Repeatability limit	r₁ = 0.350 + 0.0129 X

Table 3. Repeatability and reproducibility standard deviations
expressed as coefficient of variations.
		Level 1	Level 2	Level 3
Repeatability coefficient of variation	C_r1	1.6	1.0	0.9
Reproducibility coefficient of variation	C_R1	3.7	2.8	4.4

Table 4. Sensitivity ratios.
	Level 2 - Level 1	Level 3 - Level 2	Level 3 - Level 1
Repeatability	37.2	18.0	53.8
Reproducibility	14.5	4.5	12.9