ASTM D575-91 pdf free.Standard Test Methods for Rubber Properties in Compression.
This precision and bias section has been prepared inaccordance with Practice D 4483.Refer to Practice D 4483 forterminology and other statistical calculation details.
The precision results in this precision and bias sectiongive an estimate of the precision of this test method with thematerials (rubbers) used in the particular interlaboratory program as described in this section. The precision parametersshould not be used for acceptance/rejection testing of anygroup of materials without documentation that they are applicable to those particular materials and the specific testingprotocols that are included in this test method.
Two separate precision programs were conducted forthis test method, one in 1983 and a second in 1989.
A Type 1 (interlaboratory) precision was evaluated inboth programs.Both repeatability and reproducibility are shortterm; a period of a few days separates replicate test results.Atest result is the value，as specified by this test method,obtained on a single determination(s) or measurement(s) of theproperty or parameter in question. The third deflection cycle isused for the measurement. For the 1983 program，threedifferent materials were used;these were tested in threelaboratories on two different days.
For the 1989 program seven materials were tested innine laboratories on two separate days.
The results of the precision calculations for repeat-
ability and reproducibility are given in Tables 1-4, in ascendingorder of material average or level, for each of the mater1alsevaluated.Table 1 and Table 2 are for the 1983 program (No.
1), and Table 3 and Table 4 are for the 1989 program (No.2).14.5 The precision of this test method may be expressed inthe format of the following statements that use an “appropriatevalueof r,R,(r), or (R), to be used in decisions about testresults. The appropriate value is that value of r or R associatedwith a mean level in the precision tables closest to the meanlevel under consideration at any given time for any givenmaterial in routine testing operations.
The repeatability, r, of this test methodhas been established as the appropriate value tabulated in theprecision tables.Two single test results, obtained under normaltest method procedures, that differ by more than this tabulatedr (for any given level) must be considered as derived fromdifferent or non-identical sample populations.ASTM D575 pdf download.