ASTM_D_7778_-_15.pdf

Designation:D777815An American National StandardStandard Guide forConducting an Interlaboratory Study to Determine thePrecision of a Test Method1This standard is issued under the fixed designation D7778;the number immediately following the designation indicates 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.1.Scope*1.1 This guide describes the procedures for planning andconducting an interlaboratory study(ILS)of a test method usedin Petroleum Products and Lubricants Committee D02 ofASTM for the purpose of estimating repeatability and repro-ducibility of the test method in accordance with ASTM Formand Style requirements.1.2 This guide is concerned with the management of the ILSand intended to provide guidance for the planning stage andensure the process,logistics,and tools are identified and agreedupon in advance.1.2.1 Selection of the samples and the impact of sampleselection on the final scope of the test methodboth the rangeof materials covered in the scope and precision sections and themeasurement range covered in the precision sectionareimportant,and careful consideration needs to be given to theseaspects before an ILS is launched.1.3 This guide does not concern itself with the developmentof test methods but rather with gathering the informationneeded for a test method precision statement.1.4 This guide is concerned with test methods which yield asingle numerical figure as the test result,although the singlefigure may be the result of a calculation from a set ofmeasurements.1.5 This guide is designed for tests of properties that arestable,such that bulk samples can be homogenized andsub-samples can be prepared that will be identical and stablefor the duration of the ILS testing period.This guide is notdesigned for unstable properties or for properties that make itdifficult to obtain stable,representative samples for an ILSconducted at multiple laboratory sites.1.6 This guide represents the suggested practices for atypical precision study.Individual subcommittees may modifythis approach as their expertise directs.1.7 This guide is voluntary,and thus,is not required for anapproved precision study.2.Referenced Documents2.1 ASTM Standards:2D130 Test Method for Corrosiveness to Copper from Petro-leum Products by Copper Strip TestD4306 Practice for Aviation Fuel Sample Containers forTests Affected by Trace ContaminationD5854 Practice for Mixing and Handling of Liquid Samplesof Petroleum and Petroleum ProductsD6300 Practice for Determination of Precision and BiasData for Use in Test Methods for Petroleum Products andLubricantsD6708 Practice for Statistical Assessment and Improvementof Expected Agreement Between Two Test Methods thatPurport to Measure the Same Property of a MaterialD6792 Practice for Quality System in Petroleum Productsand Lubricants Testing LaboratoriesE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE178 Practice for Dealing With Outlying ObservationsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1169 Practice for Conducting Ruggedness Tests2.2 ISO/IEC Standards:3ISO/IEC Guide 30 Terms and Definitions Used in Connec-tion with Reference MaterialsISO/IEC Guide 17025 General Requirements for the Com-petence of Testing and Calibration Laboratories3.Terminology3.1 Definitions:1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.94.01 on Task GroupA:QualityAssurance and Quality Control.Current edition approved April 1,2015.Published May 2015.Originallyapproved in 2012.Last previous edition approved in 2012 as D7778 12.DOI:10.1520/D7778-15.2For 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 Summary page onthe ASTM website.3Available from Available from Aerospace Industries Association of America,Inc.(AIA),1000 Wilson Blvd.,Suite 1700,Arlington,VA 22209-3928,http:/www.aia-aerospace.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.1 accuracy,ncloseness of agreement between an in-dividual test result and an accepted reference value.E4563.1.2 bias,ndifference between the population mean ofthe test results and an accepted reference value.E4563.1.3 outlier,nobservation that appears to deviate mark-edly from the other observations of the sample(also referred toas extreme result,outlying or doubtful observation,or aberrantvalue.E1783.1.4 precision,ncloseness of agreement among test re-sults obtained under presc