These test methods may be used for acceptance testing of commercial shipments; however, caution is advised because information about between interlaboratory precision is incomplete. Comparative tests as directed in 5.1.1 may be advisable.

5.1.1 If there are differences of practical significance between reported test results for two laboratories (or more), comparative tests should be performed to determine if there is statistical bias between them using competent statistical assistance. As a minimum, use test samples for such comparative tests that are as homogeneous as possible, drawn from the same lot of material as the samples that resulted in the disparate results during initial testing, and that are randomly assigned in equal numbers to each laboratory for testing. The test results from the laboratories should be compared using statistical test for unpaired data at a probability level chosen prior to the testing series. If a bias is found either its cause must be found and corrected, or future test results for that material must be adjusted in consideration of the known bias.

These test methods are useful to evaluate quality and cost control during the manufacture of pile yarn floor covering.

The significance and uses of particular properties and test methods are discussed in the appropriate sections of the specified test methods.