DS/ISO Accuracy (trueness and precision) of measurement methods and results – Part 4: Basic methods for estimating the trueness of a standard. ISO Accuracy (Trueness and Precision) of Measurement Methods and Results – Part 4: Basic Methods for the Determination of the Trueness of a. Buy DS ISO ACCURACY (TRUENESS AND PRECISION) OF MEASUREMENT METHODS AND RESULTS – PART 4: BASIC METHODS FOR.
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Genauigkeit Richtigkeit und Praezision von Messverfahren und Messergebnissen. Basic methods 575-4 the determination of the trueness of a standard measurement method Status: Therefore the Index j for the level has been omitted throughout. The purpose of the two-bottle system was to confirm the absence of the between-bottle variation.
Reference materials could be either a certified reference materials; b materials manufactured for the purpose of the experiment with known properties; or c materials whose properties have been established by measurements using an alternative measure- ment method whose bias is known to be negligi- ble. Laboratory means and laboratory variances Lab. General principles and definitions – Part 2: The variation of the estimate of the bias of the measurement method is due to the variation in the results of the measurement process and is expressed by its standard deviation computed as in the case of known precision values, or siJzT-yF .
When gR is larger than T. Accuracy trueness and precision of measurement methods and results — Part 6: In the former case, the repeatability standard devi- ation of the measurement method, or, will be used for the assessment of the laboratory bias. In the latter case, it is necessary to investigate the causes of the discrep- ancy and possibly to repeat the experiment prior to proceeding further.
Outliers and stragglers Level Lab. As a result the experiment may have to be repeated to yield the expected preci- sion values.
You may find similar items within these categories by selecting from the choices below:. 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.
Here B is the laboratory component of bias, i. Related international standards ISO Learn more about the cookies we use and how to change your settings. It may appear that some laboratories did not use the required equipment or did not work ac- cording to the specified conditions. Find Similar Items This product falls into the following categories. This requires an experiment involving many laboratories, very much as described in IS0 Equations 8 to 10 as- sume an equal number n of test results in each laboratory.
Accept and continue Learn more about the cookies we use and how to change your settings. The boxed points in figures B. All measurements are to be carried out according to that standard method.
Grundlegendes Verfahren zur Schaetzung der Richtigkeit eines Messverfahrens. Alternative methods for the determi- nation of the precision of a standard measure- ment method.
BS ISO 5725-4:1994
Reference materials shall be homogeneous. This implies comparison between the within-laboratory standard deviation and the stated repeatability standard deviation of the standard measurement method.
One laboratory re- sult was identified as a straggler; it originated from the same laboratory Lab. The laboratory means and vari- ances for each of the five test materials are listed in table 8.
If the repeatability standard deviation of the standard measurement method has not been previously deter- mined in accordance with IS0s, will be con- sidered to be the best estimate of it.
The h and k values are shown in figures B. If this is not true, the respective equations given in IS0 should be used to calculate s. Accuracy trueness and precision of measurement methods and results — Part 5: IS0 consists of the following parts, under the general title Accuracy trueness and precision of measurement methods and results: My account Shoping cart 0 Help. Al- though, for some measurement methods, the true value cannot be known exactly, it may be possible to have an accepted reference value for the property being measured; for example, if suitable reference materials are available, or if the accepted reference value can be established 57254 refer- ence to another measurement method or by preparation of a known sample.
If the repeatability of the measurement method is poor, then it will not isso practical to achieve a high degree of certainty in the estimate of the bias of the laboratory. Isoo de base pour la determination de la justesse d’une methode de mesure normalisee. It is not applicable if the bias in the measurement of one property is affected by the level of a second property i.
What 575-4 should be taken with respect to re- jected outlying laboratories? Alternative methods for the determination of the precision of a standard measurement method.
Enoval – References
The test results for each level are shown in figures B. Basic method for the determination of repeatability and reproducibility of a standard measurement method. In particular, if outlying values are de- tected, all necessary steps shall be taken to investi- gate the reasons why they have been obtained, including re-appraisal of the suitability of the accepted reference value.
Intermediate measures of the precision of a standard measurement method – Part 4: Further regular testing is required to show that the labora- tory bias does not vary; the method described in IS0 may be used for this. If u, is un- known, its estimate s. If the reproducibility of the measurement method is poor, then it will not be practical to achieve a high degree of certainty in the estimate of the bias. Each laboratory re- ceived two randomly selected bottles of test sample for each level and performed duplicate analyses on each bottle.