1、Designation: D6300 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 the yea
2、r 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:D02-1007,2Manual on Determining
3、 Precision Data for ASTM Methodson Petroleum Products and Lubricants2and 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 encompasses both
4、 the determination of precision and the application of such precisiondata. In effect, it combines the type of information in RR:D02-10072regarding the determination ofthe precision estimates and the type of information in Practice D3244 for the utilization of test data.The following practice, intend
5、ed to replace RR:D02-1007,2differs slightly from related portions of theISO standard.1. Scope*1.1 This practice covers the necessary preparations andplanning for the conduct of interlaboratory programs for thedevelopment of estimates of precision (determinability,repeatability, and reproducibility)
6、and of bias (absolute andrelative), and further presents the standard phraseology forincorporating such information into standard test methods.1.2 This practice is generally limited to homogeneous prod-ucts with which serious sampling problems (such as heteroge-neity or instability) do not normally
7、arise.1.3 This practice may not be suitable for products withsampling problems as described in 1.2, solid or semisolidproducts such as petroleum coke, industrial pitches, paraffinwaxes, greases, or solid lubricants when the heterogeneousproperties of the substances create sampling problems. In suchi
8、nstances, consult a trained statistician.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the Worl
9、d Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3D3244 Practice for Utilization of Test Data to DetermineConformance with SpecificationsD3606 Test Method for Determination of Benzene andToluene in Finished Motor and Aviation Gasoline by GasCh
10、romatographyD6708 Practice for Statistical Assessment and Improvementof Expected Agreement Between Two Test Methods thatPurport to Measure the Same Property of a MaterialD7915 Practice for Application of Generalized ExtremeStudentized Deviate (GESD) Technique to Simultane-ously Identify Multiple Out
11、liers in a Data SetE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDet
12、ermine the Precision of a Test Method2.2 ISO Standards:ISO 4259 Petroleum Products-Determination and Applica-tion of Precision Data in Relation to Methods of Test41This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts, Liquid Fuels, and Lubricantsand is the direct respon
13、sibility of Subcom-mittee D02.94 on Coordinating Subcommittee on Quality Assurance and Statistics.Current edition approved July 1, 2017. Published August 2017. Originallyapproved in 1998. Last previous edition approved in 2017 as D6300 17. DOI:10.1520/D6300-17A.2Supporting data have been filed at AS
14、TM International Headquarters and maybe obtained by requesting Research Report RR:D02-1007.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Su
15、mmary page onthe ASTM website.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshoh
16、ocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organ
17、ization Technical Barriers to Trade (TBT) Committee.13. Terminology3.1 Definitions:3.1.1 analysis of variance (ANOVA), ntechnique that en-ables the total variance of a method to be broken down into itscomponent factors. ISO 42593.1.2 bias, nthe difference between the expectation of thetest results a
18、nd an accepted reference value.3.1.2.1 DiscussionThe term “expectation” is used in thecontext of statistics terminology, which implies it is a “statis-tical expectation.” E1773.1.3 between-method bias (relative bias), na quantitativeexpression for the mathematical correction that can statisticallyim
19、prove the degree of agreement between the expected valuesof two test methods which purport to measure the sameproperty. D67083.1.4 degrees of freedom, nthe divisor used in the calcu-lation of variance, one less than the number of independentresults.3.1.4.1 DiscussionThis definition applies strictly
20、only inthe simplest cases. Complete definitions are beyond the scopeof this practice. ISO 42593.1.5 determinability, na quantitative measure of the vari-ability associated with the same operator in a given laboratoryobtaining successive determined values using the same appa-ratus for a series of ope
21、rations leading to a single result; it isdefined as the difference between two such single determinedvalues that would be exceeded with an approximate probabilityof 5 % (one case in 20 in the long run) in the normal andcorrect operation of the test method.3.1.5.1 DiscussionThis definition implies th
22、at two deter-mined values, obtained under determinability conditions,which differ by more than the determinability value should beconsidered suspect. If an operator obtains more than twodeterminations, then it would usually be satisfactory to checkthe most discordant determination against the mean o
23、f theremainder, using determinability as the critical difference (1).53.1.6 mean square, nin analysis of variance, sum ofsquares divided by the degrees of freedom. ISO 42593.1.7 normal distribution, nthe distribution that has theprobability function x, such that, if x is any real number, theprobabil
24、ity density isfx! 5 1/!2!21/2exp2x 2 !2/22# (1)NOTE 1 is the true value and is the standard deviation of thenormal distribution ( 0). ISO 42593.1.8 outlier, na result far enough in magnitude from otherresults to be considered not a part of the set. RR:D02100723.1.9 precision, nthe degree of agreemen
25、t between two ormore results on the same property of identical test material. Inthis practice, precision statements are framed in terms ofrepeatability and reproducibility of the test method.3.1.9.1 DiscussionThe testing conditions represented byrepeatability and reproducibility should reflect the n
26、ormalextremes of variability under which the test is commonly used.Repeatability conditions are those showing the least variation;reproducibility, the usual maximum degree of variability. Referto the definitions of each of these terms for greater detail.RR:D02100723.1.10 random error, nthe chance va
27、riation encountered inall test work despite the closest control of variables.RR:D02100723.1.11 repeatability (a.k.a. Repeatability Limit), nthequantitative expression for the random error associated withthe difference between two independent results obtained underrepeatability conditions that would
28、be exceeded with anapproximate probability of 5 % (one case in 20 in the long run)in the normal and correct operation of the test method.3.1.11.1 DiscussionInterpret as the value equal to orbelow which the absolute difference between two single testresults obtained in the above conditions may expect
29、 to lie witha probability of 95 %. ISO 42593.1.11.2 DiscussionThe difference is related to the repeat-ability standard deviation but it is not the standard deviation orits estimate. RR:D02100723.1.12 repeatability conditions, nconditions where inde-pendent test results are obtained with the same met
30、hod onidentical test items in the same laboratory by the same operatorusing the same equipment within short intervals of time. E1773.1.13 reproducibility (a.k.a. Reproducibility Limit), naquantitative expression for the random error associated withthe difference between two independent results obtai
31、ned underreproducibility conditions that would be exceeded with anapproximate probability of 5 % (one case in 20 in the long run)in the normal and correct operation of the test method.3.1.13.1 DiscussionInterpret as the value equal to orbelow which the absolute difference between two single testresu
32、lts on identical material obtained by operators in differentlaboratories, using the standardized test, may be expected to liewith a probability of 95 %. ISO 42593.1.13.2 DiscussionThe difference is related to the repro-ducibility standard deviation but is not the standard deviationor its estimate. R
33、R:D02100723.1.13.3 DiscussionIn those cases where the normal useof the test method does not involve sending a sample to atesting laboratory, either because it is an in-line test method orbecause of serious sample instabilities or similar reasons, theprecision test for obtaining reproducibility may a
34、llow for theuse of apparatus from the participating laboratories at acommon site (several common sites, if feasible). The statisticalanalysis is not affected thereby. However, the interpretation ofthe reproducibility value will be affected, and therefore, theprecision statement shall, in this case,
35、state the conditions towhich the reproducibility value applies, and label this precisionin a manner consistent with how the test data is obtained.3.1.14 reproducibility conditions, nconditions where in-dependent test results are obtained with the same method onidentical test items in different labor
36、atories with differentoperators using different equipment.NOTE 2Different laboratory by necessity means a different operator,different equipment, and different location and under different supervisorycontrol. E1775The bold numbers in parentheses refers to the list of references at the end of thissta
37、ndard.D6300 17a23.1.15 standard deviation, nmeasure of the dispersion of aseries of results around their mean, equal to the square root ofthe variance and estimated by the positive square root of themean square. ISO 42593.1.16 sum of squares, nin analysis of variance, sum ofsquares of the difference
38、s between a series of results and theirmean. ISO 42593.1.17 variance, na measure of the dispersion of a seriesof accepted results about their average. It is equal to the sum ofthe squares of the deviation of each result from the average,divided by the number of degrees of freedom. RR:D02100723.1.18
39、variance, between-laboratory, nthat component ofthe overall variance due to the difference in the mean valuesobtained by different laboratories. ISO 42593.1.18.1 DiscussionWhen results obtained by more thanone laboratory are compared, the scatter is usually wider thanwhen the same number of tests ar
40、e carried out by a singlelaboratory, and there is some variation between means obtainedby different laboratories. Differences in operator technique,instrumentation, environment, and sample “as received” areamong the factors that can affect the between laboratoryvariance. There is a corresponding def
41、inition for between-operator variance.3.1.18.2 DiscussionThe term “between-laboratory” is of-ten shortened to “laboratory” when used to qualify represen-tative parameters of the dispersion of the population of results,for example as “laboratory variance.”3.2 Definitions of Terms Specific to This Sta
42、ndard:3.2.1 determination, nthe process of carrying out a seriesof operations specified in the test method whereby a singlevalue is obtained.3.2.2 operator, na person who carries out a particular test.3.2.3 probability density function, nfunction which yieldsthe probability that the random variable
43、takes on any one of itsadmissible values; here, we are interested only in the normalprobability.3.2.4 result, nthe final value obtained by following thecomplete set of instructions in the test method.3.2.4.1 DiscussionIt may be obtained from a single deter-mination or from several determinations, de
44、pending on theinstructions in the method. When rounding off results, theprocedures described in Practice E29 shall be used.4. Summary of Practice4.1 A draft of the test method is prepared and a pilotprogram can be conducted to verify details of the procedureand to estimate roughly the precision of t
45、he test method.4.1.1 If the responsible committee decides that an interlabo-ratory study for the test method is to take place at a later pointin time, an interim repeatability is estimated by following therequirements in 6.2.1.4.2 A plan is developed for the interlaboratory study usingthe number of
46、participating laboratories to determine thenumber of samples needed to provide the necessary degrees offreedom. Samples are acquired and distributed. The interlabo-ratory study is then conducted on an agreed draft of the testmethod.4.3 The data are summarized and analyzed. Any depen-dence of precisi
47、on on the level of test result is removed bytransformation. The resulting data are inspected for uniformityand for outliers. Any missing and rejected data are estimated.The transformation is confirmed. Finally, an analysis of vari-ance is performed, followed by calculation of repeatability,reproduci
48、bility, and bias. When it forms a necessary part of thetest procedure, the determinability is also calculated.5. Significance and Use5.1 ASTM test methods are frequently intended for use inthe manufacture, selling, and buying of materials in accordancewith specifications and therefore should provide
49、 such precisionthat when the test is properly performed by a competentoperator, the results will be found satisfactory for judging thecompliance of the material with the specification. Statementsaddressing precision and bias are required in ASTM testmethods. These then give the user an idea of the precision ofthe resulting data and its relationship to an accepted referencematerial or source (if available). Statements addressing deter-minability are sometimes required as part of the test methodprocedure in order to provide early
