rank sum test in R vs. MATLAB: exact p-value when ties are ...

Dear masters of R and MATLAB! As documented, the rank sum test in R can not yield the exact p-value when the data has ties: Home Public Questions Tags Users Companies Collectives ExploreCollectives Teams StackOverflowforTeams –Startcollaboratingandsharingorganizationalknowledge. CreateafreeTeam WhyTeams? Teams CreatefreeTeam Collectives™onStackOverflow Findcentralized,trustedcontentandcollaboratearoundthetechnologiesyouusemost. LearnmoreaboutCollectives Teams Q&Aforwork Connectandshareknowledgewithinasinglelocationthatisstructuredandeasytosearch. LearnmoreaboutTeams ranksumtestinRvs.MATLAB:exactp-valuewhentiesarepresent AskQuestion Asked 7monthsago Modified 7monthsago Viewed 83times 0 New!Savequestionsoranswersandorganizeyourfavoritecontent.Learnmore. DearmastersofRandMATLAB! Asdocumented,theranksumtestinRcannotyieldtheexactp-valuewhenthedatahasties: x=c(1,1,100,1000,10000);y=c(2,20,20,2000,20000); result=wilcox.test(x,y,mu=0,paired=FALSE, conf.level=0.95,exact=TRUE,alternative='greater') Warningmessage: Inwilcox.test.default(x,y,mu=0,paired=FALSE,conf.level=0.95,: cannotcomputeexactp-valuewithties Result Wilcoxonrank-sumtestwithcontinuitycorrection data:xandy W=10,p-value=0.7358 alternativehypothesis:truelocationshiftisgreaterthan0 BUTMATLABDOESIT: x=[1,1,100,1000,10000]';y=[2,20,20,2000,20000]'; [p,h,stats]=ranksum(x,y,'alpha',0.05,'method','exact','tail','right') p=0.714285714285714 Iguess,MATLABdoesanillegalthing(pMATLAB=0.71,not0.74),BUTiwouldneedtoforceRtoyieldtheexactp-value(pEXACT=pMATLAB=0.71)fortestingpurposes. Thankyou:) rmatlab Share Improvethisquestion Follow editedMar19at14:03 Kat 10.6k22goldbadges1414silverbadges3838bronzebadges askedMar19at9:05 MichaelJachanMichaelJachan 122bronzebadges 2 MatlabandRbothadjustfortiesusingnormaldistribution,butexecutethisdifferently.ForMatlab,seeGibbonsandChakraborti(2010)&HollanderandWolfe(1999).ForR,seeBauer(1972).Neitheriswrong,it'sjustdifferentperspectivesofthesameproblem. – Kat Mar19at14:15 Thx,Kat!Isee,thereareseveralstrategies.ButthecoreofmyQis:CanigenerateRandMATLAB-commands,suchthatbothyieldthesameresults?BR,MJ:) – MichaelJachan Mar21at2:27 Addacomment  |  0 Sortedby: Resettodefault Highestscore(default) Trending(recentvotescountmore) Datemodified(newestfirst) Datecreated(oldestfirst) Knowsomeonewhocananswer?Sharealinktothisquestionviaemail,Twitter,orFacebook. 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