1、Designation: D6300 17D6300 17a 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 (such as heterogeneityor instability) do n
7、ot normally arise.1.3 This practice may not be suitable for products with sampling problems as described in 1.2, solid or semisolid products suchas petroleum coke, industrial pitches, paraffin waxes, greases, or solid lubricants when the heterogeneous properties of thesubstances create sampling prob
8、lems. In such instances, consult a trained statistician.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
9、by the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 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 Gas
10、oline by Gas Chromatog-raphyD6708 Practice for Statistical Assessment and Improvement of Expected 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 Iden
11、tifyMultiple Outliers in a Data SetE29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications1 This practice is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility of SubcommitteeD02
12、.94 on Coordinating Subcommittee on Quality Assurance and Statistics.Current edition approved May 1, 2017July 1, 2017. Published June 2017August 2017. Originally approved in 1998. Last previous edition approved in 20162017 asD6300 16a.D6300 17. DOI: 10.1520/D6300-17.10.1520/D6300-17A.2 Supporting da
13、ta have been filed at 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 t
14、he standards Document 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 a
15、ccurately, ASTM recommends 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 Har
16、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1E177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2 IS
17、O Standards:ISO 4259 Petroleum Products-Determination and Application of Precision Data in Relation 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 b
18、ias, nthe difference between the expectation of the test results and an accepted reference value.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
19、expression for the mathematical correction that can statisticallyimprove the degree of agreement 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 ind
20、ependent results.3.1.4.1 DiscussionThis definition applies strictly only in the simplest cases. 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 succe
21、ssive determined values using the same apparatus for a series of operations leading to a single result; it is definedas the difference between two such single determined values that would be exceeded with an approximate probability of 5 % (onecase in 20 in the long run) in the normal and correct ope
22、ration of the test method.3.1.5.1 DiscussionThis definition implies 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 besat
23、isfactory to check the most discordant determination against 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 th
24、e probability function x, such that, if x is any real number, 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 n
25、ot a part of the set. RR:D02100723.1.9 precision, nthe degree 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 cond
26、itions represented by repeatability and reproducibility should 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
27、 these terms for greater detail.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 references at the end of this standard.D6300 17a23.1.10 random error, nt
28、he chance variation encountered in all test work despite the closest control of variables.RR:D02100723.1.11 repeatability (a.k.a. Repeatability Limit), nthe quantitative expression for the random error associated with thedifference between two independent results obtained under repeatability conditi
29、ons that would be exceeded with an approximateprobability of 5 % (one case in 20 in the long run) in the normal and correct operation of the test method.3.1.11.1 DiscussionInterpret as the value equal to or below which the absolute difference between two single test results obtained in the abovecond
30、itions may expect to lie with a probability 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
31、with the same method on identical testitems in the same laboratory by the same operator using the same equipment within short intervals of time. E1773.1.13 reproducibility (a.k.a. Reproducibility Limit), na quantitative expression for the random error associated with thedifference between two indepe
32、ndent results obtained under reproducibility conditions that would be exceeded with an approximateprobability of 5 % (one case in 20 in the long run) in the normal and correct operation of the test method.3.1.13.1 DiscussionInterpret as the value equal to or below which the absolute difference betwe
33、en two single test results on identical 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 devi
34、ation or its estimate. RR:D02100723.1.13.3 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 obta
35、iningreproducibility may allow for the 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 st
36、atement shall, in this case, state the conditions to which the reproducibility value applies.applies, andlabel this precision in a manner consistent with how the test data is obtained.3.1.14 reproducibility conditions, nconditions where independent test results are obtained with the same method on i
37、denticaltest items in different laboratories with different operators using different equipment.NOTE 2Different laboratory by necessity means a different operator, different equipment, and different location and under different supervisorycontrol. E1773.1.15 standard deviation, nmeasure of the dispe
38、rsion of a series of results around their mean, equal to the square root of thevariance and estimated by the positive square root 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 v
39、ariance, na measure of the dispersion of a series of accepted results about their average. It is equal to the sum of thesquares of 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 overal
40、l variance due to the difference in the mean valuesobtained by different laboratories. ISO 42593.1.18.1 DiscussionWhen results 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 v
41、ariation between means obtained by different laboratories. DifferencesD6300 17a3in operator technique, instrumentation, environment, 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
42、.2 DiscussionThe term “between-laboratory” is often shortened to “laboratory” when used to qualify representative parameters of the 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 car
43、rying out a series of operations specified in the test method whereby a single valueis obtained.3.2.2 operator, na person who carries 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; he
44、re, we are interested only in the normal probability.3.2.4 result, nthe final value obtained by following the complete set of instructions 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.
45、Whenrounding off results, the procedures described in Practice E29 shall be used.4. Summary of Practice4.1 Adraft of the test method 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 co
46、mmittee decides that an interlaboratory study for the test method is to take place at a later point intime, an interim repeatability 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 t
47、he number ofsamples needed to provide the necessary degrees of freedom. Samples are acquired and distributed. The interlaboratory 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
48、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 necessar
49、y part of the test procedure, the determinability is also calculated.5. Significance and Use5.1 ASTM test methods are frequently intended for use in the manufacture, selling, and buying of materials in accordance withspecifications and therefore should provide such precision that when the test is properly performed by a competent operator, theresults will be found satisfactory for judging the compliance of the material with the specification. Statements addressing precisionand bias are required in ASTM test methods. These
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