12. Precision and Bias
12.1 Precision - The precision of this test method as obtained by statistical examination of interlaboratory test results from eleven samples of motor gasoline, covering concentration range of 0.25 to 40 mg/L manganese, run in duplicate by eleven laboratories is as follows:
12.1.1 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 following values only in one case in twenty:
where x = average of the two results.
12.1.2 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 following values only in one case in twenty:
where x = average of the two results.
12.2 Bias - The bias for the procedure in this test method cannot be determined, since a suitable reference material is not available.
13. Keywords
13.1 AAS; atomic absorption spectroscopy; gasoline; manganese; methylcyclopentadienyl manganese tricarbonyl; MMT