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

It is necessary, for a split-level experiment, that the two sirnilar materials used at a level of the experiment are so simitar that they can be expected to give the same repeatability and reproducibility standard deviations. This is performed on dumbell-shaped specimens BS specifies the number of such specimens to cut from a hide, and also their position and orientation within the hide, so the natural definition of a “sample” to use when testing leather is a complete hide.

Basic methods for the determination of the trueness of a standard ixo method Part 5: Methods for determination of particle size distribution. B informative Derivation of the factors used in algorithms A and S Figure 4 shows that, in 5725–5 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 iao.

## BS ISO 5725-5:1998

Label sio samples so that this is possible, and ieo careful not to disclose this informationto the participants. 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. The approach that is used in the examples that follow is to use the iterative method to find an approximate solution, then solve equation 68 to find the exact solution.

E The repeatability standard aviation srj, between-samples standard deviation sW, between-laboratory standard deviation sLp and reproducibility standard deviation sR using: The ISO Accuracy of Measurement Methods and Results Package provides the general principles necessary to accurately assess measurement methods, results, applications and practical estimations.

For example, with the data from one level of the uniform-level design considered in IS0the first stage of the analysis is to calculate the average and standard deviation of the measurement results in each cell. Please download Chrome or Firefox or view our browser tips. Calculation of the sum of squares for repeatability 6 Robust methods for data analysis 6. The use of robust estimates of the standard deviations as is denominators in the h and k statistics, 572-5 of robust estimates iwo the overall averages in the calculation of the h statistics, avoids this distortion.

Hisher decision will have a substantial influence on the calculated values for the repeatability and reproducibility standard deviations. Assemble the data into a table as shown in table 9. Usually, because of considerations of cost, the answer will be two.

It is therefore recommended that they are used for this purpose. The other laboratories form a group in the middle of the plot. Royal Society of Chemistry, London. To test for stragglers and outliers in the cell averages, apply Grubbs’ tests to the values in each column of table 3 in turn. The second term on the right-hand side of 8.

Iand use this quantity as described in IS0 You may delete a document from your Alert Profile at any time. Laboratory 5 gives a point in the bottom left-hand corner of the graph, and Laboratory 1 gives a point in the top right-hand corner: It is stated there that for estimating the accuracy trueness and precision of a measurement method, it is useful to assume that every measurement result is the sum of three components: Initially the test portion is prepared so that it is all retained on a 10,Omm sieve.

They do not combine individual test results in a robust manner,?.

If the participants in the experiment can be considered to be divided into two classes, those that produce good-quality data, and those that produce poor-quality data, then the robust methods should yield values for the repeatability and reproducibility standard deviations that are valid for the good-quality-data class, and not affected by the poor-quality data provided that the poor-quality-dataclass is not too large.

Consistency check on between-test-result ranges grouped by laboratory c l n m 1 2 3 4 5 L 6 Laboratory 7 lild 8 9 10 1 1 Figure 6 – Example 2: You may experience issues viewing this site in Internet Explorer 9, 10 or Each combination of a laboratory and a level gives jso “cell” in this table, izo two items of data, yiia iwo ygb.

This is why it is important that the two materials should be similar.

They are used to identify results that are so inconsistent with the remainder of the data reported in the experiment that their inclusion in the calculation of the repeaiability and reproducibility standard deviations would affect the values of these statistics substantially.

The two samples within a level are denoted U and isso a represents a sample of one material, and b represents a sample of the other, similar, material. Also, the h statistics for Laboratories 1, 2 and 6 indicate a bias that changes with 5752-5 in each of these laboratories.

Standards Subsctiption may be the perfect solution.

If data are rejected, recalculate the statistics. If the calculations are being done by hand, the data analyst should use the direct method described in 6.

These tests again indicate that the data from Laboratory 5 are suspect. The analysis would then continue with an investigation of possible functional relationships between the repeatability and reproducibility standard deviations and the general average. The general case is considered in 5. The calculations required by the more general design are much more complicated than those required by the case with two test results per sample and 57255- samples per laboratory per level.

We use cookies to make our website easier to use and to better understand your needs. The laboratory effects for each i with summation over r and k: An example is given in figure 1. Level 5 in that example is of particular interest because Laboratory 1 gave a cell average that was shown to be a near-straggler by Grubbs’ test, and Laboratory 6 gave a cell range that was shown to be a nearstraggler isp Cochran’s test. However, data should not be discarded as a result of these tests and checks.