ASTM D6300 - 17

    Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants

    Active Standard ASTM D6300 | Developed by Subcommittee: D02.94

    Book of Standards Volume: 05.03


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    Significance and Use

    5.1 ASTM test methods are frequently intended for use in the manufacture, selling, and buying of materials in accordance with specifications and therefore should provide such precision that when the test is properly performed by a competent operator, the results will be found satisfactory for judging the compliance of the material with the specification. Statements addressing precision and bias are required in ASTM test methods. These then give the user an idea of the precision of the resulting data and its relationship to an accepted reference material or source (if available). Statements addressing determinability are sometimes required as part of the test method procedure in order to provide early warning of a significant degradation of testing quality while processing any series of samples.

    5.2 Repeatability and reproducibility are defined in the precision section of every Committee D02 test method. Determinability is defined above in Section 3. The relationship among the three measures of precision can be tabulated in terms of their different sources of variation (see Table 1).

    TABLE 1 Sources of Variation

     

    Method

    Apparatus

    Operator

    Laboratory

    Time

    Reproducibility

    Complete

    Different

    Different

    Different

    Not Specified

     

    (Result)

     

     

     

     

    Repeatability

    Complete

    Same

    Same

    Same

    Almost same

     

    (Result)

     

     

     

     

    Determinability

    Incomplete

    Same

    Same

    Same

    Almost same

     

    (Part result)

     

     

     

     

    5.2.1 When used, determinability is a mandatory part of the Procedure section. It will allow operators to check their technique for the sequence of operations specified. It also ensures that a result based on the set of determined values is not subject to excessive variability from that source.

    5.3 A bias statement furnishes guidelines on the relationship between a set of test results and a related set of accepted reference values. When the bias of a test method is known, a compensating adjustment can be incorporated in the test method.

    5.4 This practice is intended for use by D02 subcommittees in determining precision estimates and bias statements to be used in D02 test methods. Its procedures correspond with ISO 4259 and are the basis for the Committee D02 computer software, Calculation of Precision Data: Petroleum Test Methods. The use of this practice replaces that of Research Report RR:D02-1007.2

    5.5 Standard practices for the calculation of precision have been written by many committees with emphasis on their particular product area. One developed by Committee E11 on Statistics is Practice E691. Practice E691 and this practice differ as outlined in Table 2.

    TABLE 2 Differences in Calculation of Precision in Practices D6300 and E691

    Element

    This Practice

    Practice E691

    Number of replicates

    Two

    Any number

     

     

     

    Precision is written
    for

    Test method

    Each sample

     

     

     

    Outlier tests:
     Within laboratories
     Between laboratories

    Sequential
     Cochran test
     Hawkins test

    Simultaneous
    k-value
    h-value

     

     

     

    Outliers

    Rejected, subject to subcommittee approval.

    Rejected if many laboratories or for cause such as blunder or not following method.

     

     

     

     

    Retesting not generally permitted.

    Laboratory may retest sample having rejected data.

     

     

     

    Analysis of variance

    Two-way, applied globally
    to all the remaining data
    at once.

    One-way, applied to each sample separately.

     

     

     

    Precision multiplier

    t Equation D6300-17_2 , where t is the two-tailed Student's t for 95 % probability.

    Equation D6300-17_3

     

     

     

     

    Increases with decreasing laboratories × samples particularly below 12.

    Constant.

     

     

     

    Variation of precision with level

    Minimized by data transformation. Equations
    for repeatability and reproducibility are generated in the retransformation process.

    User may assess from individual sample precisions.

    1. Scope

    1.1 This practice covers the necessary preparations and planning for the conduct of interlaboratory programs for the development of estimates of precision (determinability, repeatability, and reproducibility) and of bias (absolute and relative), and further 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 may 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 developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    D3244 Practice for Utilization of Test Data to Determine Conformance with Specifications

    D3606 Test Method for Determination of Benzene and Toluene in Finished Motor and Aviation Gasoline by Gas Chromatography

    D6708 Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport to Measure the Same Property of a Material

    D7915 Practice for Application of Generalized Extreme Studentized Deviate (GESD) Technique to Simultaneously Identify Multiple Outliers in a Data Set

    E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications

    E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods

    E456 Terminology Relating to Quality and Statistics

    E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

    ISO Standards

    ISO 4259 Petroleum Products-Determination and Application of Precision Data in Relation to Methods of Test Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.


    ICS Code

    ICS Number Code 03.120.20 (Product and company certification. Conformity assessment); 75.080 (Petroleum products in general)

    Referencing This Standard
    Link Here
    Link to Active (This link will always route to the current Active version of the standard.)

    DOI: 10.1520/D6300-17

    Citation Format

    ASTM D6300-17, Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants, ASTM International, West Conshohocken, PA, 2017, www.astm.org

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