ASTM_E_1488_-_12e1.pdf

Designation:E1488121An American National StandardStandard Guide forStatistical Procedures to Use in Developing and ApplyingTest Methods1This standard is issued under the fixed designation E1488;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.1NOTEEditorial corrections were made to 3.1.25 in April 2013.1.Scope1.1 This guide identifies statistical procedures for use indeveloping new test methods or revising or evaluating existingtest methods,or both.1.2 This guide also cites statistical procedures especiallyuseful in the application of test methods.2.Referenced Documents2.1 ASTM Standards:2E177 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 TestsE1402 Guide for Sampling DesignE2282 Guide for Defining the Test Result of a Test MethodE2489 Practice for Statistical Analysis of One-Sample andTwo-Sample Interlaboratory Proficiency Testing ProgramsE2554 Practice for Estimating and Monitoring the Uncer-tainty of Test Results of a Test Method Using ControlChart TechniquesE2586 Practice for Calculating and Using Basic StatisticsE2587 Practice for Use of Control Charts in StatisticalProcess ControlE2655 Guide for Reporting Uncertainty of Test Results andUse of the Term Measurement Uncertainty in ASTM TestMethods3.Terminology3.1 DefinitionsFor a more extensive list of terms in E11standards,see Terminology E456.3.1.1 bias,nthe difference between the expectation of thetest results and an accepted reference value.E1773.1.1.1 DiscussionStatistical procedures include the sam-pling considerations or the experiment design for the collectionof data,or both,and the numerical and graphical approaches tosummarize and analyze the collected data.3.1.2 coeffcient of variation,CV,nfor a nonnegativecharacteristic,the ratio of the standard deviation to the meanfor a population or sample.E25863.1.3 component of variance,na part of a total varianceidentified with a specified source of variability.3.1.4 control chart,nchart on which are plotted a statis-tical measure of a subgroup versus time of sampling along withlimits based on the statistical distribution of that measure so asto indicate how much common,or chance,cause variation isinherent in the process or product.E25873.1.5 observation,nthe process of obtaining informationregarding the presence or absence of an attribute of a testspecimen,or of making a reading on a characteristic ordimension of a test specimen.E22823.1.6 observed value,nthe value obtained by making anobservation.E22823.1.7 precision,nthe closeness of agreement betweenindependent test results obtained under stipulated conditions.E1773.1.8 proficiency testing,ndetermination of laboratorytesting performance by means of interlaboratory comparisons.E24893.1.9 repeatability,nprecision under repeatability condi-tions.E1773.1.10 repeatability conditions,nconditions where inde-pendent test results are obtained with the same method onidentical test items in the same laboratory by the same operatorusing the same equipment within short intervals of time.E1771This guide is under the jurisdiction of ASTM Committee E11 on Quality andStatistics and is the direct responsibility of Subcommittee E11.20 on Test MethodEvaluation and Quality Control.Current edition approved Aug.1,2012.Published September 2012.Originallyapproved in 1992.Last previous edition approved in 2009 as E1488 09.DOI:10.1520/E1488-12E01.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.11 repeatability limit r,nthe value below which theabsolute difference between two individual test results obtainedunder repeatability conditions may be expected to occur with aprobability of approximately 0.95(95%).E1773.1.12 repeatability standard deviation,sr,n the standarddeviation of test results obtained under repeatability condi-tions.E1773.1.13 reproducibility,nprecision under reproducibilityconditions.E1773.1.14 reproducibility conditions,nconditions where testresults are obtained with the same method on identical testitems in different laboratories with different operators usingdifferent equipment.E1773.1.15 reproducibility limit,R,nthe value below whichthe absolute difference between two test results obtained underreproducibility conditions may be expected to occur with aprobability of