1、Designation: D6300 16aD6300 17 An American National StandardStandard Practice forDetermination of Precision and Bias Data for Use in TestMethods for Petroleum Products and Lubricants1This standard is issued under the fixed designation D6300; the number immediately following the designation indicates
2、 the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONBoth Research Report RR:D02-1007,2 Manual on De
3、termining Precision Data for ASTM Methodson Petroleum Products and Lubricants2 and the ISO 4259, benefitted greatly from more than 50 yearsof collaboration between ASTM and the Institute of Petroleum (IP) in the UK. The more recent workwas documented by the IP and has become ISO 4259.ISO 4259 encomp
4、asses both the determination of precision and the application of such precisiondata. In effect, it combines the type of information in RR:D02-10072 regarding the determination ofthe precision estimates and the type of information in Practice D3244 for the utilization of test data.The following pract
5、ice, intended to replace RR:D02-1007,2 differs slightly from related portions of theISO standard.1. Scope*1.1 This practice covers the necessary preparations and planning for the conduct of interlaboratory programs for thedevelopment of estimates of precision (determinability, repeatability, and rep
6、roducibility) and of bias (absolute and relative), andfurther presents the standard phraseology for incorporating such information into standard test methods.1.2 This practice is generally limited to homogeneous products with which serious sampling problems do not normally arise.1.3 This practice ma
7、y not be suitable for solid or semisolid products such as petroleum coke, industrial pitches, paraffin waxes,greases, or solid lubricants when the heterogeneous properties of the substances create sampling problems. In such instances,consult a trained statistician.1.4 This international standard was
8、 developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced D
9、ocuments2.1 ASTM Standards:3D3244 Practice for Utilization of Test Data to Determine Conformance with SpecificationsD3606 Test Method for Determination of Benzene and Toluene in Finished Motor and Aviation Gasoline by Gas Chromatog-raphyD6708 Practice for Statistical Assessment and Improvement of Ex
10、pected Agreement Between Two Test Methods that Purportto Measure the Same Property of a MaterialD7915 Practice for Application of Generalized Extreme Studentized Deviate (GESD) Technique to Simultaneously IdentifyMultiple Outliers in a Data SetE29 Practice for Using Significant Digits in Test Data t
11、o Determine Conformance with SpecificationsE177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods1 This practice is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility of SubcommitteeD02.94 on Coordinati
12、ng Subcommittee on Quality Assurance and Statistics.Current edition approved July 1, 2016May 1, 2017. Published August 2016June 2017. Originally approved in 1998. Last previous edition approved in 2016 asD6300 16.D6300 16a. DOI: 10.1520/D6300-16A.10.1520/D6300-17.2 Supporting data have been filed at
13、 ASTM International Headquarters and may be obtained by requesting Research Report RR:D02-1007.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document
14、 Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recom
15、mends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C70
16、0, West Conshohocken, PA 19428-2959. United States1E456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2 ISO Standards:ISO 4259 Petroleum Products-Determination and Application of Precision Data in Rela
17、tion to Methods of Test43. Terminology3.1 Definitions:3.1.1 analysis of variance (ANOVA), ntechnique that enables the total variance of a method to be broken down into itscomponent factors. ISO 42593.1.2 bias, nthe difference between the expectation of the test results and an accepted reference valu
18、e.3.1.2.1 DiscussionThe term “expectation” is used in the context of statistics terminology, which implies it is a “statistical expectation.” E1773.1.3 between-method bias (relative bias), na quantitative expression for the mathematical correction that can statisticallyimprove the degree of agreemen
19、t between the expected values of two test methods which purport to measure the same property.D67083.1.4 degrees of freedom, nthe divisor used in the calculation of variance, one less than the number of independent results.3.1.4.1 DiscussionThis definition applies strictly only in the simplest cases.
20、 Complete definitions are beyond the scope of this practice. ISO 42593.1.5 determinability, na quantitative measure of the variability associated with the same operator in a given laboratoryobtaining successive determined values using the same apparatus for a series of operations leading to a single
21、 result; it is definedas thatthe difference between two such single determined values asthat would be exceeded in the long run in only one with anapproximate probability of 5 % (one case in 20 in the long run) in the normal and correct operation of the test method.3.1.5.1 DiscussionThis definition i
22、mplies that two determined values, obtained under determinability conditions, which differ by more than thedeterminability value should be considered suspect. If an operator obtains more than two determinations, then it would usually besatisfactory to check the most discordant determination against
23、the mean of the remainder, using determinability as the criticaldifference (1).53.1.6 mean square, nin analysis of variance, sum of squares divided by the degrees of freedom. ISO 42593.1.7 normal distribution, nthe distribution that has the probability function x, such that, if x is any real number,
24、 theprobability density isfx!51/!2!21/2exp2x 2! 2/22# (1)NOTE 1 is the true value and is the standard deviation of the normal distribution ( 0). ISO 42593.1.8 outlier, na result far enough in magnitude from other results to be considered not a part of the set. RR:D02100723.1.9 precision, nthe degree
25、 of agreement between two or more results on the same property of identical test material. In thispractice, precision statements are framed in terms of repeatability and reproducibility of the test method.3.1.9.1 DiscussionThe testing conditions represented by repeatability and reproducibility shoul
26、d reflect the normal extremes of variability underwhich the test is commonly used. Repeatability conditions are those showing the least variation; reproducibility, the usualmaximum degree of variability. Refer to the definitions of each of these terms for greater detail.RR:D02100723.1.10 random erro
27、r, nthe chance variation encountered in all test work despite the closest control of variables.RR:D02100724 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.5 The bold numbers in parentheses refers to the list of reference
28、s at the end of this standard.D6300 1723.1.11 repeatability, repeatability (a.k.a. Repeatability Limit), nthe quantitative expression offor the random error associatedwith the same operator in a given laboratory obtaining repetitive results by applying the same test method with the same apparatusund
29、er constant operating conditions on identical test material within short intervals of time. It is defined as the difference betweentwo such results at the 95 % confidence level.difference between two independent results obtained under repeatability conditionsthat would be exceeded with an approximat
30、e probability of 5 % (one case in 20 in the long run) in the normal and correct operationof the test method. RR:D02100723.1.11.1 DiscussionInterpret as the value equal to or below which the absolute difference between two single test results obtained in the aboveconditions may expect to lie with a p
31、robability of 95 %. ISO 42593.1.11.2 DiscussionThe difference is related to the repeatability standard deviation but it is not the standard deviation or its estimate. RR:D02100723.1.12 repeatability conditions, nconditions where independent test results are obtained with the same method on identical
32、 testitems in the same laboratory by the same operator using the same equipment within short intervals of time. E1773.1.13 reproducibility, reproducibility (a.k.a. Reproducibility Limit), na quantitative expression offor the random errorassociated with different operators from different laboratories
33、 using different apparatus, each obtaining a single result by applyingthe same test method on an identical test sample. It is defined as the 95 % confidence limit for the difference between two suchsingle and independent results. the difference between two independent results obtained under reproduc
34、ibility conditions thatwould be exceeded with an approximate probability of 5 % (one case in 20 in the long run) in the normal and correct operationof the test method.3.1.13.1 DiscussionInterpret as the value equal to or below which the absolute difference between two single test results on identica
35、l material obtainedby operators in different laboratories, using the standardized test, may be expected to lie with a probability of 95 %. ISO 42593.1.13.2 DiscussionThe difference is related to the reproducibility standard deviation but is not the standard deviation or its estimate. RR:D02100723.1.
36、13.3 DiscussionIn those cases where the normal use of the test method does not involve sending a sample to a testing laboratory, either becauseit is an in-line test method or because of serious sample instabilities or similar reasons, the precision test for obtainingreproducibility may allow for the
37、 use of apparatus from the participating laboratories at a common site (several common sites, iffeasible). The statistical analysis is not affected thereby. However, the interpretation of the reproducibility value will be affected,and therefore, the precision statement shall, in this case, state the
38、 conditions to which the reproducibility value applies.3.1.14 reproducibility conditions, nconditions where independent test results are obtained with the same method on identicaltest items in different laboratories with different operators using different equipment.NOTE 2Different laboratory by nec
39、essity means a different operator, different equipment, and different location and under different supervisorycontrol. E1773.1.15 standard deviation, nmeasure of the dispersion of a series of results around their mean, equal to the square root of thevariance and estimated by the positive square root
40、 of the mean square. ISO 42593.1.16 sum of squares, nin analysis of variance, sum of squares of the differences between a series of results and their mean.ISO 42593.1.17 variance, na measure of the dispersion of a series of accepted results about their average. It is equal to the sum of thesquares o
41、f the deviation of each result from the average, divided by the number of degrees of freedom. RR:D02100723.1.18 variance, between-laboratory, nthat component of the overall variance due to the difference in the mean valuesobtained by different laboratories. ISO 42593.1.18.1 DiscussionD6300 173When r
42、esults obtained by more than one laboratory are compared, the scatter is usually wider than when the same number of testsare carried out by a single laboratory, and there is some variation between means obtained by different laboratories. Differencesin operator technique, instrumentation, environmen
43、t, and sample “as received” are among the factors that can affect the betweenlaboratory variance. There is a corresponding definition for between-operator variance.3.1.18.2 DiscussionThe term “between-laboratory” is often shortened to “laboratory” when used to qualify representative parameters of th
44、e dispersionof the population of results, for example as “laboratory variance.”3.2 Definitions of Terms Specific to This Standard:3.2.1 determination, nthe process of carrying out a series of operations specified in the test method whereby a single valueis obtained.3.2.2 operator, na person who carr
45、ies out a particular test.3.2.3 probability density function, nfunction which yields the probability that the random variable takes on any one of itsadmissible values; here, we are interested only in the normal probability.3.2.4 result, nthe final value obtained by following the complete set of inst
46、ructions in the test method.3.2.4.1 DiscussionIt may be obtained from a single determination or from several determinations, depending on the instructions in the method. Whenrounding off results, the procedures described in Practice E29 shall be used.4. Summary of Practice4.1 Adraft of the test meth
47、od is prepared and a pilot program can be conducted to verify details of the procedure and to estimateroughly the precision of the test method.4.1.1 If the responsible committee decides that an interlaboratory study for the test method is to take place at a later point intime, an interim repeatabili
48、ty is estimated by following the requirements in 6.2.1.4.2 A plan is developed for the interlaboratory study using the number of participating laboratories to determine the number ofsamples needed to provide the necessary degrees of freedom. Samples are acquired and distributed. The interlaboratory
49、study isthen conducted on an agreed draft of the test method.4.3 The data are summarized and analyzed. Any dependence of precision on the level of test result is removed bytransformation. The resulting data are inspected for uniformity and for outliers. Any missing and rejected data are estimated. Thetransformation is confirmed. Finally, an analysis of variance is performed, followed by calculation of repeatability, reproducibility,and bias. When it forms a necessary part of the test procedure, the determinability is als
