ASTM D4931 Standard Test Method for Gross Moisture in Green Petroleum Coke
10. Precision and Bias
10.1 Precision - The precision of total moisture as determined in 9.1.3 by the statistical examination of the interlaboratory test results is as follows:
10.1.1 Repeatability - The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test method, exceed the following values only one case in twenty.
Repeatability = 0.34%
10.1.2 Reproducibility - The difference between two single and independent results obtained by different operators working in different laboratories on identical material would, in the long run, exceed the following values only in one case in twenty.
Reproducibility = 0.58%
NOTE 2 - The values in the statements were determined in a cooperative program following RR:D02-1007.
10.2 The precision for ADL moisture as determined by Step 8.1 was not determined in this program. It is believed that there would be no difference in the precision.
10.3 The interlaboratory program included six duplicate petroleum coke samples with nine laboratories participating.
10.4 Bias - Since there is no accepted reference material for determining the bias for this test method for measuring the gross moisture in green petroleum coke, no statement on bias is being made.
11. Keywords
11.1 air drying loss (ADL); free water; green petroleum coke; residual moisture; total moisture
