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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Trueness refers to the closeness of agreement between the average value of a large number of test results and the true or accepted reference value. Also, the h statistics for Laboratories 1, 2 and 6 indicate a bias that changes with level in each of these laboratories. The robust methods described in this clause allow the data to be analysed in such a way that it is not required to make decisions that affect the results of the calculations.
One approach is to try the various possibilities in a systematic order?.
However, data should not be discarded as a result of these tests and checks. These are given in table 8. To test a sand, a bulk sample is taken from the product, then one or more test portions are produced from the bulk sample. Basic method for the determination of repeatability and reproducibiiity of a standard measurement method. To test for stragglers and outliers in the between-test-resultranges, calculate Cochran’s statistic for each levelj as: Also in this design, the cell standard deviations are pooled to give an estimate of the repeatability standard deviation.
Royal Society of Chemistry, London. C informative Derivation of equations used for robust analysis The second term on the right-hand side of 8. This standard is also available to be included in Standards Subscriptions. Consider the results of the outlier tests in Example 1 of 4. This is strong evidence that there are consistent biases in most laboratories, indicating that the test method is not adequately specified.
Alternative methods for the determination of the precision of a standard measurement method Part 6: All standards are subject to revision, and parties to agreements based on this part of IS0 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below.
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. Need more than one copy? Wiley, New York, Robust methods for data analysis To obtain the reproducibilitystandard deviation, use equation 76 in 6.
In practice it is often found that some laboratories achieve poorer repeatability than others. Your Alert Profile lists the documents that will be monitored. 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. The p participating laboratories are each provided with two samples at q levels, and obtain two test results on each sample.
BS ISO 5725-5:1998
This is laid down, by the action of wind or water, in strata that always contain graduations in particle size, so when sand is used the particle size distribution is always of interest.
Consistencycheck on cell averages grouped by laboratory 5 A design for a heterogeneous material 5. Table 17 gives the results of the calculations for the other levels.
An experiment on a heterogeneous material 5.
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 a laboratory is achieving results that are generally biased, then it will show up as having h statistics mostly in one direction on sio graph derived from the cell averages.
Calculate the cell differences Dg. In the split-level design, each participating laboratory is provided laboratory standard jso 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 materials differ.
ISO Accuracy of Measurement Methods and Results Package
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 made that affect the results of the calculation.
Accept and continue Learn more about the cookies we use and how to change your settings. It is reasonable to assume that the variation between samples is random, does not depend on the laboratory, but may depend on the level of the experiment, so the term Hiil has a zero expectation, and a variance: To isoo the uncertainty of the estimate of the bias of the measurement method 57255-5 a split-level experiment, calculate the quantity A as defined by equation 13 of IS0 When the material is a natural or manufactured product, it can be difficult to 57255- two products that are sufficiently similar for the purposes of a split-level experiment: In the sand example discussed in 5.
The values for all levels are plotted in figures 2 and 3. The design for a heterogeneous material 575-5 in this part of IS0 yields information about the variability between samples which is not obtainable from the basic method; it may be used to calculate an estimate of reproducibilityfrom which the between-sample variation has been removed.
The general case is considered in 5.
Your basket is empty. You may experience issues viewing this site in Internet Explorer 9, 10 or This will not be so if some stages of the specimen preparation are shared by several specimens, so that a bias or isi introduced by the preparation will have a common influence on the test results derived from these specimens.