ASTM D747-02 pdf free.Standard Test Method for Apparent Bending Modulus of Plastics by Means of a Cantilever Beam.
Table 2 is based on a round-robin test conducted in 1981，in accordance with Practice E 691，involving four materials tested by seven laboratories. Each“test result” was the average of five individual determinations. Each laboratory obtained two test results for each material.
NoTE 5- Caution: The fllowing explanations ofr and R(12-1.23) are intended only to present a meaningful way of considering the approximate precision of this test method. The data given in Table 2 should not be applied rigorously to the acceptance or rejection of materials, as those data are specife to the round robin and may not be representative of other lots, conditions, matrials, or laboratories. Users of this test method should apply the principles oulined in Practice E 691 to generate data specifle to their laboratory and materials, or between specifle laboratonies. The principles of 11.2-11.23 would then be valid for such data. Concept ofr andR in Table 1- -IfS, and SR have been calculated from a large enough body of data, and for test results that were averages ftom testing five specimens for each test result, then: Repeatability- -Two test results obtained within one laboratory shall be judged not equivalent if they differ by more than the r value for that material. The r value is the interval representing the critical difference between two test results for the same material, obtained by the same operator using the same equipment on the same day in the same laboratory. Reproducibility- -Two test results obtained by differxnt laboratories shall be judged not equivalent if they difer by more than the R value for that material. The R value is the interval representing the critical difference between two test results for the same material, obtained by different operators using different equipment in different laboratories. The judgments in 112.1 and 11.2.2 will have an approximately 95 % (0.95) probability of being correct. Bias- -No statement may be made about the bias of this test method, as there is no standard reference material or reference test method that is applicable. ASTM D747 pdf download.