ASTM D3775-17e1

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

5.1.2 This test method is suitable for use with narrow fabrics when the count across the total width is measured in the narrow direction and extrapolated to the number of yarns per centimeter (inch).

1.2.1 Throughout this document, there will be some instances in which the units do not convert 1:1. This is to acknowledge that this is a global document and that different parts of the world use different units of measurement. Organizations using the metric system wil report the count per 1 cm. Organizations using the English system will report the count per 1 in.