ASTM_D_6582_-_00.pdf

Designation:D 6582 00Standard Guide forRanked Set Sampling:Efficient Estimation of a MeanConcentration in Environmental Sampling1This standard is issued under the fixed designation D 6582;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide describes ranked set sampling,discusses itsrelative advantages over simple random sampling,and pro-vides examples of potential applications in environmentalsampling.1.2 Ranked set sampling is useful and cost-effective whenthere is an auxiliary variable,which can be inexpensivelymeasured relative to the primary variable,and when theauxiliary variable has correlation with the primary variable.The resultant estimation of the mean concentration is unbiased,more precise than simple random sampling,and more repre-sentative of the population under a wide variety of conditions.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:D 5792 Practice for Generation of Environmental DataRelated to Waste Management Activities:Development ofData Quality Objectives2D 6044 Guide for Representative Sampling for Manage-ment of Waste and Contaminated Media23.Terminology3.1 Definitions:3.1.1 auxiliary variable,nthe secondary characteristic ormeasurement of interest.3.1.1.1 DiscussionIn ranked set sampling,informationcontained in an auxiliary variable is useful for ranking thesamples.This ranking may mimic the rankings of the sampleswith respect to the values of the primary variable when there iscorrelation between the auxiliary variable and the primaryvariable.Auxiliary information may include visual inspection,inexpensive quick measurement,knowledge of operationalhistory,previous site data,or any other similar information.3.1.2 data quality objectives(DQO)process,na qualitymanagement tool based on the scientific method and developedby the U.S.Environmental Protection Agency(EPA)to facili-tate the planning of environmental data collection activities.(D 5792)3.1.3 equal allocation,nthis occurs when the number ofsets in ranked set sampling is an integer multiple of the size ofthe set.3.1.4 primary variable,nthe primary characteristic ormeasurement of interest.3.1.5 ranked set sampling,na sampling method in whichsamples are ranked by the use of auxiliary information on thesamples and only a subset of the samples are selected for themeasurement of the primary variable.3.1.6 representative sample,na sample collected in such amanner that it reflects one or more characteristics of interest(asdefined by the project objectives)of a population from whichit is collected.(D 6044)3.1.6.1 DiscussionArepresentative sample can be a singlesample,a collection of samples,or one or more compositesamples.A single sample can be representative only when thepopulation is highly homogeneous.(D 6044)4.Significance and Use4.1 Ranked set sampling is cost-effective,unbiased,moreprecise and more representative of the population than simplerandom sampling under a variety of conditions(1).34.2 Ranked set sampling(RSS)can be used when:4.2.1 The population is likely to have stratification inconcentrations of contaminant.4.2.2 There is an auxiliary variable.4.2.3 The auxiliary variable has strong correlation with theprimary variable.4.2.4 The auxiliary variable is either quick or inexpensive tomeasure,relative to the primary variable.4.3 This guide provides a ranked set sampling method onlyunder the rule of equal allocation.This guide is intended forthose who manage,design,and implement sampling andanalysis plans for management of wastes and contaminatedmedia.This guide can be used in conjunction with the DQOprocess(see Practice D 5792).1This guide is under the jurisdiction of ASTM Committee D34 on WasteManagement and is the direct responsibility of Subcommittee D34.01.01 onPlanning for Sampling.Current edition approved Aug.10,2000.Published October 2000.2Annual Book of ASTM Standards,Vol 11.04.3The boldface numbers in parentheses refer to the list of references at the end ofthis standard.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.5.Ranked Set Sampling(RSS)5.1 Environmental sampling typically requires the identifi-cation of the locations where the samples are to collected.Subsequent analyses of these samples to quantify the charac-teristics of interest allow inference on the population meanconcentration from the sample data.5.2 A simple random sampling(SRS)approach is onesampling design that can be used.In this case,a set of randomsamples is identified and collecte