ASTM D3238 Standard Test Method for Calculation of Carbon Distribution and Structural Group Analysis of Petroleum Oils by the n-d-M Method
8. Precision and Bias
8.1 The precision of this test as obtained by statistical examination of interlaboratory test results is as follows:
8.1.1 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 values shown in the following table only in one case in twenty:
8.1.2 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 values shown in the following table only in one case in twenty:
8.2 Bias - Bias cannot be determined because there are no reference materials suitable for determining the bias of this test method.
9. Keywords
9.1 carbon distribution; ring content; refractive index; density; molecular weight; petroleum oils