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1.
The analytical data received in an inter-laboratory study of four Canadian reference samples were treated by two different methods in order to arrive at "usable values" for the concentration of each constituent. The first method ("Select Laboratories"), proposed by S. Abbey (S.A.), is based on the fact that some laboratories consistently produce better results than others. S.A. suggests an approach which permits isolation of results from such laboratories, calculation of a mean or a median of such results and use of one or the other as the concentration of a constituent. That approach involves a degree of subjectivity and S.A. attempts to demonstrate the validity of his approach by means of several tests applied to the results obtained for the four samples.  相似文献   
2.
Using the compiled analytical data for the constituents of four Canadian iron-formation reference samples, a comparison is made among nine different "robust" estimators of "true" value, including the median, median, Gastwirth median, trimean, quarter-trimmed and sixthtrimmed means and the three Hampel estimators. Individual estimators and combinations of them are compared by means of the summation and "iron-oxide compatibility" tests. Comparisons are also made with values derived by the "select laboratories" method.  相似文献   
3.
A comparison is made between various measures proposed thus far for deducing the "best values" from discordant data received in the course of collaborative analysis of proposed reference rocks. Using the raw data on three Canadian samples and the summation and "iron-oxide compatibility" tests, it is claimed that the "select laboratories" method produces the best results.  相似文献   
4.
Because of the disparate data, reported in collaborative analyses of reference samples of rooks, various methods have been proposed for deriving "best values". This work compares those methods and several additional ones. Included are two simplified estimates of "mode" which yield values close to those of the Dominant Cluster and Gamma Transformation methods. An example is also cited of the hazards that may result from too superficial reading of raw data.  相似文献   
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Using a recently published compilation of analytical data on reference samples SY-2, SY-3 and MRG-1 as an example, a case is presented in favor of more precise terminology in describing analytical methods used in reporting data in collaborative programs. The technique of final measurement in a particular method is often less important than earlier operations, such as sample attack or technique of separation.  相似文献   
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Based on the most recent compilation of analytical data, a new set of “usable values” is calculated for six of the best known silicate rock reference samples produced by the U.S. Geological Survey. The latest version of the “best laboratories” method is described and results are compared with other recently published values.  相似文献   
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Reviews already published on the state of “standard samples” of silicate rocks and minerals, as well as of some samples of other materials that can be used as reference standards for the general analysis of silicate rocks and minerals, have been updated. Usable values of varying degrees of reliability are suggested for major, minor and trace constituents of nearly one hundred different samples. Presentation of the information has been improved with a view to making it more convenient for readers’use.  相似文献   
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