Cooperative test

Bowen, C. W., Phelps, A. J. (1997). Demonstration-based cooperative testing in general chemistry A broader assessment-of-leaming technique. Journal of Chemical Education, 74, 715-719. 

Estimation of the limits of accuracy (deviation from a true or theoretical value) is not ordinarily attempted in coal analysis. Precision, on the other hand, is determined by means of cooperative test programs. Both repeatability, the precision with which a test can be repeated in the same laboratory, usually but not always by the same analyst using the same equipment and following the prescribed method(s), and reproducibility, the precision expected of results from different laboratories, are determined. Values quoted in test methods are the differences between two results that should be exceeded in only 5 out of 100 pairs of results, equal to 2-Jl times the standard deviation of a large population of results. 

In a series of standard deviations, variances, or ranges the COCHRAN test [ISO 5725] is used for evaluating the largest value. It is primarily used in (planned) method comparisons, cooperative tests, and analysis of variance where the number of the measurements and the levels of the means should be the same. 

Without going too deeply into details we will refer to cooperative tests ( round robins , interlaboratory comparisons) in which two basic aims are ... 

Participation in cooperative tests is an important means of external quality assurance. 

For demonstration we use the data of a cooperative test [DOERFFEL and ZWANZIGER, 1987], In this interlaboratory comparison five laboratories were involved in the analysis of slag samples three times for seven chemical elements. So the (15, 7)-data matrix consists of 5 times 3 rows and 7 columns. The raw data in % are given in Tab. 5-2. The data have been preprocessed by standardization (autoscaling). 

Fig. 5-14. Clustering of the objects (samples) from a cooperative test...

Bowen CW, Phelps AJ (1997) Demonstration-based cooperative testing in general chemistry a broader assessment-of-learning technique. J Chem Educ 74(6) 715—720. 

Winterburn, G. (1988) Cooperative Test Results of Apparent Viscosity Determination at Low Shear Rates using the Constant Pressure Viscometer, NLGI Spokesman LII (8), 365-372. PoweU, T. W. (1982) Activators for Organophilic Clays in Lubricating Greases, NLGI Spokesman XLVI (8) 269-277. 

TABLE X Cooperative Tests on Iron Catalysts at Schwartzheide Product Distribution in Weight Per Cent ... 

Estimation of the limits of accuracy (deviation from a true or theoretical value) is not ordinarily attempted in coal analysis. Precision, on the other hand, is determined by means of cooperative test... 

Nevertheless, ISO 9223 and 9224 (following on earlier work by Knotkova et al., 1975 Barton et al., 1979, Barton, Knotknova, et al., 1980, Holler, Knotkova, et al., 1986) have tables based on many cooperative tests and should be given careful consideration by specifiers if the necessary atmospheric data are available. The danger of relying on such tables is that other significant factors that vary considerably from place to place (such as... 

The lack of correlation in impact testing results was confirmed and explained by the results of a Cooperative Test Program conducted by the Wright Air De-... 

W. M. Orr, "Results of Lox-Lubricant Impact Sensitivity Cooperative Test Program," Technical Note No. 58-344, Wright Air Development Center, Dayton, Ohio (November, 1958). 

Cooperative testing through Corrosion Coordinating Committees 18... 

The names and addresses of the sponsor, testing facility, investigators/ cooperators test sites. The dated signatures of the study director and the sponsor ... 

Although the wheel test is used sometimes in persistency testing, care must be taken to minimize an increase in inhibitor concentration in the uninhibited fluids through carryover from the treated metal sample. A good review of this method and its results is given in a report of a cooperative test carried out by an NACE Task Group T-ID-2 on evaluation of film persistency. 

ASTM Test Method D1218, Refractive Index and Refractive Dispersion of Hydrocarbon Liquids, is designed to use the Bausch Lomb Precision Refractometer. This model is no longer manufactured. ASTM Test Method D1747, Refractive Index of Viscous Materials, uses the Abbe t3T>e (Valentine) refractometer, which is no longer made. In both cases, other refractometers are available, but no cooperative work has been conducted to verify equivalence. There are also limitations on the availability of thermometers with suitable range and accuracy that will fit the instruments. ASTM Subcommittee D02.04.0D plans cooperative testing of modem commercial refractometers to develop precision data, but data are not yet available. 

Note 10—The precision data were developed in a 1991 cooperative test program using eight (8) samtdes. Twdve (12) laboratories partici pated with the manual apparatus and seventeen (17) laboratories participated with the automatic equipment Information on the type of samples and their average flashpoints are in the research report available at ASTM Headquarters. 

Fig. XI.1) has been derived by ASTM Committee D-2 from the cooperative testing of 18 reinesentative petroleum products and confirmed by further data on about ISO samfdes... 

Relative Bias—Tbsstt is no statistically significant bias between Procedures A and B for gasolines as determined in the last cooperative test program. 

The results of the cooperative test program from which these values have been derived are filed at ASTM Headquarters, 1916 Race SL, Philaddphia, PA 19103. Request RR D02-I24S. 

The actual values for these standards are established and annually reaffirmed by cooperative tests. In 1991, tests were made using 15 different types of viscometers In 28 laboratories located In 14 countries. 

X2.1 No exact correlation of the results obtained by the two test methods exists because of the empirical nature of the two tests. However, an approximate correlation (Fig. X2.1) has been derived from the cooperative testing by ASTM Committee D-2 of 18 representative petroleum products and confirmed by further data on about 150 samples which were... 

Not determined ftom recent cooperative tests however, the ratios with those given in the I9S3 venhm are believed to apply. 

Note AS.l—It has been established by cooperative tests that observed aniline points determined by some automatic apparatus are lower than the determinations by Methods A and B. The diflerence is greater for automatic apparatus when relatively high sample-cooling rates are used, and increases as the aniline point increases. 

Precision data have not been established for all types of samples on which this test method is used. Limited cooperative tests were conducted in 1961, principally to establish equality with the previously used shaking procedure. Preci-... 

Specific bias has not been established by cooperative testing. 

The bias for this test method has not been determined. Subcommittee EX)2.04.0D plans to cooperatively test modern refractometers and determine the bias. 

XI. 1 The following four partition columns have been cooperatively tested and found suitable for use with materials given in the scope of this test method. 

Note I—K 22 by 28-in. (SS9 by 711-mm) chart available as an adjunct to this test method was used in cooperative testing of the method. If other charts are used, the precision statements given in the Precision Section will not apply. 

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