ISO 5725-5:1998 pdf download.Accuracy (trueness and precision) of measurement methods and results
1 Scope
This part of ISO 5725
- provides detailed descriptions of alternatives to the basic method for determining the repeatability and reproducibility standard deviations of a standard measurement method, namely the split-level design and a design for heterogeneous materials;
- describes the use of robust methods for analysing the results of precision experiments without using outlier tests to exclude data from the calculations, and in particular, the detailed use of one such method.
This part of ISo 5725 complements ISO 5725-2 by providing alternative designs that may be of more value in some situations than the basic design given in ISO 5725-2, and by providing a robust method of analysis that gives estimates of the repeatability and reproducibility standard deviations that are less dependent on the data analyst's judgement than those given by the methods described in ISO 5725-2.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO 5725. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO 5725 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISo maintain registers of currently valid International Standards.
ISO 3534-1:1993, Statistics一Vocabulary and symbols一Part 1: Probability and general statistical terms.
ISO 3534-3:1985, Statistics一Vocabulary and symbols - - Part 3: Design of expeniments.
ISO 5725-1:1994, Accuracy (trueness and precision) of measurement methods and results 一Part 1: General principles and definitions.
ISO 5725-2:1994, Accuracy (trueness and precision) of measurement methods and results一Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method.
4.1 Applications of the split-level design
4.1.1 The uniform level design described in ISO 5725-2 requires two or more identical samples of a material to be tested in each participating laboratory and at each level of the experiment. With this design there is a risk that an operator may allow the result of a measurement on one sample to influence the result of a subsequent measurement on another sample of the same material. If this happens, the results of the precision experiment will be distorted: estimates of the repeatability standard deviation σr will be decreased and estimates of the between-laboratory standard deviation OL will be increased. In the split-level design, each participating laboratory is provided with a sample of each of two similar materials, at each level of the experiment, and the operators are told that the samples are not identical, but they are not told by how much the materials differ. The split-level design thus provides a method of determining the repeatability and reproducibility standard deviations of a standard measurement method in a way that reduces the risk that a test result obtained on one sample will influence a test result on another sample in the experiment.
ISO 5725-5.ISO 5725-5 pdf download.