Refer to the particular test method cited for the property of interest for specific significance and use statements.

In case of a dispute arising from the differences in reported test values when using the test methods listed in these test methods for acceptance testing of commercial shipments, the purchaser and the supplier should conduct comparative tests to determine whether a statistical bias exists between their laboratories. Competent statistical assistance is recommended for the investigation of this bias. As a minimum, the two parties should take a group of test specimens that are as homogeneous as possible and that are from a lot of material of the type in question. The test specimens should then be assigned randomly, in equal numbers, to each laboratory for testing. The average results from the two laboratories should be compared using Student' t-test for unpaired data and an acceptable probability level chosen by the two parties before the testing is begun. If a bias is found, either its cause must be determined and corrected or the purchaser and supplier must agree to interpret future results in the light of the known bias.