数据分析软件PAST-paleontological-statistics-software-pac

PAST-PAlaeontologicalSTatisticsØyvindHammer,D.A.T.Harper,P.D.RyanMay21,20011IntroductionWelcometothePAST!Thisprogramisdesignedasafollow-uptoPALSTAT,anextensivepackagewrittenbyP.D.Ryan,D.A.T.HarperandJ.S.Whalley(Ryanetal.1995).Itincludesanumberoffunctionswhicharecommonlyusedinpalaeon-tologyandpalaeoecology.Thesedays,anumberoflargeandverygoodstatisticssystemsexist,includingSPSSandExcel.Whyyetanotherstatisticsprogram?PASTisfree.PASTistailor-madeforpalaeontology.Thismeansboththatitincludesfunctionswhicharenotfoundinoff-the-shelfprograms(forexamplecladis-tics,ordinationandgeometricalanalysis),andthatitdoesnotincludefunc-tionswhichareoflittleusetopalaeontologistsandthatonlymaketheuserinterfacemoreconfusing.PASTiseasytouse,andthereforewellsuitedforintroductorycoursesinquantitativepalaeontology.PASTcomeswithanumberofexampledatasets,casestudiesandexercises,makingitacompleteeducationalpackage.FurtherexplanationsofmanyofthetechniquesimplementedtogetherwithcasehistoriesarelocatedinHarper(1999).Ifyouhavequestions,bugreports,suggestionsforimprovementsorothercom-ments,[e-mail]~ohammer/past12InstallationThebasicinstallationofPASTiseasy:Justdownloadthefile’Past.exe’andputitanywhereonyourharddisk.Double-clickingthefilewillstarttheprogram.Thedatafilesforthecasestudiescanbedownloadedseparately,ortogetherinthepackedfile’casefiles.zip’.ThisfilemustbeunpackedwithaprogramsuchasWinZip.Wesuggestyoumakeafoldercalled’past’anywhereonyourharddisk,andputallthefilesinthisfolder.Pleasenote:ProblemshavebeenreportedforsomecombinationsofscreenresolutionanddefaultfontsizeinWindows-thelayoutgetsuglyanditmaybenecessaryfortheusertoincreasethesizesofwindowsinordertoseeallthetextandbuttons.Ifthishappens,pleasesetthefontsizeto’Smallfonts’intheScreencontrolpanelinWindows.Weareworkingonsolvingthisproblem.PASTalsoseemstohaveproblemswithsomeprinters.PostscriptprintersfromHPandTektronixworkfine.23EnteringandmanipulatingdataPASThasaspreadsheet-likeuserinterface.Dataareenteredinanarrayofcells,organizedinrows(horizontally)andcolumns(vertically).EnteringdataToinputdatainacell,clickonthecellwiththemouseandtypeinthedata.Thiscanonlybedonewhentheprogramisinthe’Editmode’.Toselecteditmode,ticktheboxabovethearray.Wheneditmodeisoff,thearrayislockedandthedatacannotbechanged.Thecellscanalsobenavigatedusingthearrowkeys.Anytextcanbeenteredinthecells,butalmostallfunctionswillexpectnum-bers.PleasenotethedecimalpointconventionwhichhasbeenchosenbyWindowsdependinguponyournationality:Acomma(,)oradot(fullstop).’Dotted’datacanbe’commatized’fromtheEditmenu.Absence/presencedataarecodedas0or1,respectively.Anyotherpositivenumberwillbeinterpretedaspresence.TheconventioninPASTisthatitemsoccupyrows,andvariablescolumns.Threebrachiopodindividualsmightthereforeoccupyrows1,2and3,withtheirlengthsandwidthsincolumnsAandB.Clusteranalysiswillalwaysclusteritems,thatisrows.ForQ-modeanalysisofassociations,samples(sites)shouldthere-forebeenteredinrows,whiletaxa(species)areincolumns.Forswitchingbe-tweenQ-modeandR-mode,rowsandcolumnscaneasilybeinterchangedusingtheTransposeoperation.CommatizeConvertsallfullstops(’.’)inthedatamatrixtocommas(’,’).Thismaybeneces-saryfortheprogramtoreaddecimalpointscorrectly,dependingonyournational-ity.SelectingareasMostoperationsinPASTarecarriedonlyoutontheareaofthearraywhichyouhaveselected(marked).Ifyoutrytorunafunctionwhichexpectsdata,andnoareahasbeenselected,youwillgetanerrormessage.Arowisselectedbyclickingontherowlabel(leftmostcolumn).Acolumnisselectedbyclickingonthecolumnlabel(toprow).Multiplerowsareselectedbyselectingthefirstrowlabel,thenshift-clicking(clickingwiththeShiftkeydown)ontheadditionalrowlabels.Notethatyoucannot’dragout’multiplerows-thiswillinsteadmovethefirstrow(seebelow).3Multiplecolumnsaresimilarlymarkedbyshift-clickingtheadditionalcol-umnlabels.Thewholearraycanbeselectedbyclickingtheupperleftcornerofthearray(theemptygreycell)orbychoosing’Selectall’intheEditmenu.Smallerareaswithinthearraycanbeselectedby’draggingout’thearea,butthisonlyworkswhen’Editmode’isoff.RenamingrowsandcolumnsWhenPASTstarts,rowsarenumberedfrom1to99andcolumnsarelabelledAtoZ.Foryourownreference,andforproperlabellingofgraphs,youshouldgivetherowsandcolumnsmoredescriptivebutshortnames.Choose’Renamecolumns’or’Renamerows’intheEditmenu.Youmusthaveselectedthewholearray,orasmallerareaasappropriate.IncreasingthesizeofthearrayBydefault,PASThas99rowsand26columns.Ifyoushouldneedmore,youcanaddrowsorcolumnsbychoosing’Morerows’or’Morecolumns’intheEditmenu.Whenloadinglargedatafiles,rowsand/orcolumnsareaddedautomaticallyasneeded.MovingaroworacolumnAroworacolumn(includingitslabel)canbemovedsimplybyclickingonthelabelanddraggingtothenewposition.Cut,copy,pasteThecut,copyandpastefunctionsarefoundintheEditmenu.Notethatyoucancut/copydatafromthePASTspreadsheetandpasteintootherprograms,forex-ampleWordandExcel.Likewise,datafromotherprogramscanbepastedintoPAST.Rememberthatlocalblocksofdata(notallrowsorcolumns)canonlybem