ISO 5725-5 PDF
ISO 英文 – INTERNATIONAL STANDARD IS0 TECHNICAL CORRIGENDUM 1 Published ISO Accuracy (Trueness and Precision) of Measurement Methods and Results – Part 5: Alternative Methods for the Determination of the Precision of a. Find the most up-to-date version of ISO at Engineering
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ISO Accuracy of Measurement Methods and Results Package
The analysis would then continue with an investigation of possible functional relationships between the repeatability and reproducibility standard deviations and the general average. The data for Level 14 see table 4 are used here to illustrate the results that are obtained by robust analysis.
In an experiment on a heterogeneous material, the 5275-5 of applying these tests should be acted on in the following order. Reference number IS0 For an experiment with a heterogeneous material, this model is expanded to become: However, the principles 55725-5 the jso general design are the same as for the simple design, so the calculations will be set out in detail here for the simple design. The p participating laboratories are each provided with two samples at q levels, and obtain two test results on each sample.
A split-level experiment – Determination of protein Hisher decision will have a substantial influence on the calculated values for the repeatability and reproducibility standard deviations. It is a common experience when analysing data from precision experiments to find data that are on the borderline between stragglers and outliers, so that judgements may have to be 5275-5 that affect the results of the calculation.
The symbols used in IS0 are given in annex A. The samples were approximately kg in mass they were used for a number of other testsand the test portions were approximately g in mass.
BS ISO 5725-5:1998
Wiley, New York, It should be noted, however, that they provide a means of combining, in a robust manner, cell averages, cell standard deviations and cell ranges.
Figure 7 shows consistent positive or negative h statistics in most laboratories with Laboratories 1, 6 and 10 again achieving the largest values. Thus each cell in the experiment contains four test results two 7525-5 results for each of two samples.
The figure also shows that the results for Laboratory 4 are unusual, as the point 57725-5 this laboratory is some distance from the line of equality for the two samples. It also specifically provides a procedure for obtaining intermediate measures of precision, basic methods for the determination of the trueness of a measurement method, the determination of repeatability and reproducibility of a standard measurement method.
To test for stragglers and outliers in the cell averages, apply Grubbs’ tests to the values in each sio of table 3 in turn. Detectable ratio between the repeatability standard deviations of method B and method A True value of a standard deviation Component in a test result representing the variation due to time since last calibration Detectable ratio between the square roots of the between-laboratory mean squares of method B and method A p-quantile of the 2-distribution with u degrees of freedom P l2 Option b wastes data, but allows the simple formulae to be used.
To obtain the reproducibilitystandard deviation, use equation 76 in 6. Also, the h statistics for Laboratories 1, 2 and 6 indicate a bias that changes with iwo in each of these laboratories. For example, when the test result is the proportion of an element obtained by chemical analysis, the repeatability and reproducibility standard deviations usually increase as the proportion of the element increases.
This website is best viewed with browser version of up to Microsoft Internet Explorer 8 or Firefox 3. In the split-level design, each participating laboratory is provided laboratory standard deviation c 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 jso differ. Applying Algorithm A to the cell averages gives the results shown in table 26,where now 5725- cell averages have been sorted into increasing order.
IS0 consists of the following parts, under the general title Accuracy trueness and precision of measurement methods and results: Hence, in IS0 The interpretation of these graphs is discussed fully in subclause 7.
Probability and general statistical terms. Alternative methods for the determination of the precision of a standard measurement method. In the leather example discussed in 5. Figure 4 shows that, in this experiment, at Level 6, there is wide variation between the cell averages, so that, if the test method were to be used in a specification, it is likely that disputes would arise between vendors and purchasers because of differences in their results.
E The repeatability standard aviation srj, between-samples standard deviation sW, between-laboratory standard deviation sLp and reproducibility standard deviation sR using: The residuals for each i ,t and k: It is also necessary to specify the number of iiso that are to be averaged to give a test result, because this affects the values of the repeatability and reproducibility ieo deviations. When robust methods are used, the outlier tests and consistency checks described in IS0 or IS0 should be applied to the data, and the causes of any outliers, or patterns in the h and k statistics, should be investigated.
Such interactions between the laboratories and the levels may provide clues as to the causes of the laboratory biases. Annexes B, C and D are for information only.
You may find similar items within these categories by selecting from the choices below:. They do not combine individual test results in a robust manner,?. Subscription pricing is determined by: A further possibility is to use the iterative method to find an approximate solution, then solve equations 62 and 63 to find the exact solution.
The analysis of variance. To check the is of the cell differences, calculate the h statistics as: If there are empty cells in table 2, p is now the number of cells in column j of table 2 containing data and the summation is performed over non-empty cells.
Examine the data for consistency using the h and k statistics, described in subclause 7. Company organization, management and quality. However, the h statistics for all the other laboratories for that level will be small, even if some of these other laboratories give outliers.
Equation 67 in 6. In figure 3, the h statistics for cell averages show that Laboratory 5 gave negative h statistics at all levels, indicating a consistent negative bias in their data.
Formulae for calculating values for the repeatability and reproducibility standard deviations for the general design are given below in 5. This part of IS0 should be read in conjunction with IS0 because the underlying definitions and general principles are given there. An application of the general formulae Industrial Quality Control, 15,pp.
Plot these statistics to show up inconsistent laboratories, by plotting the statistics in the order of the levels, but also grouped by laboratory.