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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It should be noted, however, that they provide a means of combining, in a robust manner, cell averages, cell standard deviations and cell ranges.
The method of analysis requires each difference to be calculated in the same sense a-b and the sign of the difference to be retained. The values for all levels are plotted in figures 5 to 7. Methods for determination of soundness. However, the h statistics for all the other laboratories for that level will be small, even if some of these other laboratories give outliers.
Plot these statistics to show up inconsistent laboratories, by plotting the statistics in the order of the levels, but also grouped by laboratory. If a laboratory is achieving poor repeatability then it will give unusually large k statistics in the graph that is derived from the be?
Please download Chrome or Firefox or view our browser tips. W t h cadi, tevet, t w o feeds were used having similar mass fraction of protein in feed.
BS ISO 5725-5:1998
It is also necessary to specify the number of determinations that are to be averaged to give a test result, because this affects the values of the repeatability and reproducibility standard deviations. This part of IS0 describes alternative methods to this basic method.
Table 17 gives the results of the calculations for the other levels. However, the above equation may be derived by replacing p in equation 9 of IS0 The samples were approximately kg in mass they were used for a number of other testsand the test portions were approximately g in mass.
A method that is used to measure their ability to do this is the magnesium sulfate soundness test [21, in which a test portion of aggregate is subjected to a number of cycles of soaking in saturated magnesium sulfate solution, followed by drying.
ISO Accuracy of Measurement Methods and Results Package
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 could then be continued with an investigation of functional relationships, in the same way as with the uniform level design considered in IS0 In practice it is often found that some laboratories achieve poorer repeatability than others.
This is useful when it is possible to investigate the causes of the largest laboratory biases with the aim of taking corrective action. The faster, easier way to work with standards. If the document is revised or amended, you will be notified by email. If a laboratory is achieving results that are generally biased, then it will show up as having h statistics mostly in one direction on the graph derived from the cell averages.
Methods for determination of particle size distribution. The jso method requires tests for outliers to be used to identify data that should be excluded from the calculation of the repeatability and reproducibility standard deviations.
The estimate of the between-laboratorystandard deviation is thus, from equation 72 in 6. To assess the uncertainty of the estimate of a laboratory bias in a split-level experiment, calculate the quantity Aas defined by equation 16 of IS0 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.
The statistician, in this situation, has to decide between: NOTES 1 It may be of interest to perform a significance test to see if the variation between samples is statistically significant, however, this is not a necessary part of the analysis.
Between-sample ranges for Level 6 Between-sample Table 16 -Example 2: Journal of the Association of Official Analytical Chemists, 72, ,pp. Note that q depends on the degrees of freedom of s. Calculation of the sum of squares for samples i 1 Sum of squares for Degrees of freedom for samples: Examine the data for consistency using the h and k isso, described in subclause 7.
To test for stragglers and outliers in the between-test-resultranges, 7525-5 Cochran’s statistic for each levelj as: Label the samples so that this is possible, and be careful not to disclose this informationto the participants.
However, the principles of the more general design are the same as for the simple design, so the calculations will be set out in detail here for the simple design. Probability and general statistical terms.
This figure thus provides a case for investigatingthe causes of the biases at the three laboratories.
Table 2 – 5725–5 form for tabulation of cell differencesfor the split-level design Laboratory 1 1 2 I! To analyse the data using the robust methods described here, ‘Algorithm A is applied to the cell averages, and ‘Algorithm S’ is applied to each series of ranges in turn. 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.
B informative Derivation of the factors used in algorithms A and S