ASTM D4625 Method for Middle Distillate Fuel Storage Stability at 43°C (110°F)
13. Report
13.1 Report Ti, Fi, and Ai from 12.1 for both bottles to show repeatability of tests at each aging period.
14. Precision and Bias
14.1 The precision of this test method as determined by the statistical examination of the interlaboratory test results is as follows.
NOTE 4 - The precision of this method was determined in a cooperative test involving ten laboratories and eight different fuels. The results ranged from 0.1 to 11.8 mg/100 mL.
14.2 Repeatability - The difference between successive 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 (see Fig. 3).
Repeatability = 0.62√X
where:
X = the average of two results, mg/100 mL.
14.3 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, exceed the following values only in one case in twenty (see Fig. 3).
Reproducibility = 2.20√X
where:
X = the average value of two results, mg/100 mL.
14.4 Bias - The nature of this test and the parameters being measured are such that a true bias statement cannot be written.
14.5 These precision data were obtained by statistical examination in interlaboratory tests.
15. Keywords
15.1 accelerated test; adherent insolubles; distillate fuel; filterable insolubles; prediction; storage stability
