ASTM D2502 Test Method for Estimation of Molecular Weight (Relative Molecular Mass) of Petroleum Oils From Viscosity Measurements
6. Precision and Bias
6.1 The precision of this test method as obtained by statistical examination of interlaboratory test results is as follows:
6.1.1 Repeatability - The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the value 3 g/mol only in one case in twenty.
6.1.2 Reproducibility - The difference between two single and independent results, obtained by different operators, working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the value 25 g/mol only in one case in twenty.
6.2 Bias - Since there is no accepted reference material suitable for determining bias for this test method, no statement of bias can be made.
6.3 The precision for this test method was not obtained in accordance with RR:D02-1007, "Manual on Determining Precision Data for ASTM Methods on Petroleum Products and Lubricants".
7. Keywords
7.1 kinematic viscosity; molecular weight; petroleum oils; relative molecular mass
