1.1 This practice covers design and analysis of interlaboratory
testing of a test procedure in the case where the resulting test data
are discrete variates or are continuous variates not normally
distributed. This practice applies to all such interlaboratory tests
used to validate a test procedure.
1.2 Analysis of interlaboratory test results permits validation that
the process of using the test method is in statistical control and
provides the information required to write statements on precision and
bias as directed in Practice D 2906. It also gives the information for
determining the number of specimens per unit in the laboratory sample
as required in Practice D 2905.
1.3 Precision statements for non-normally distributed data can be
written as a function of the level of the property of interest without
an interlaboratory test if the underlying distribution is known and
statistical control can be assumed.
1.4 If the underlying distribution is unknown, the precision of the
test method can only be approximated. There are no generally accepted
methods of making approximations of this sort.
1.5 If statistical control cannot be assumed, then a meaningful
precision statement cannot be written and the test method should not
1.6 This practice is intended for use with data from test methods that
cannot be properly modeled by a normal distribution. See Practices D
2904 and E 691 for applications that can be modeled by a normal
1.7 This practice includes the following sections:
1.8 This standard does not purport to address all of the safety
concerns, if any, associated with its use. It is the responsibility of
whoever uses this standard to consult and establish appropriate safety
and health practices and determine the applicability of regulatory
limitations prior to use.
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