Inthe2000PresidentialelectionintheU.S.withDemocraticcandidateAlGoreandRepublican candidate GeorgeW.Bush,somepoliticalanalyststhoughtthatmostofthevotesinPalm BeachCounty,Florida,fortheReformpartycandidate,PatBuchanan,mayhaveactually beenintendedforGore(whosenamewasnexttoBuchanan’sontheballot)butwronglycast for Buchananbecauseofthedesignofthe“butterflyballot”usedinthatcounty,whichmany votersfoundconfusing.The BushGore data filecontainstheFloridacounty-widevotesforthe Reform partycandidatesin2000(Buchanan)andin1996(RossPerot).

(a) ConstructascatterplotforpredictingtheBuchananvotein2000basedonthePerotvote in 1996.Arethereanyapparentoutliersforalinearregressionmodel?

(b) Fitthelinearmodelto(i)allobservations,(ii)allbuttheobservationforPalmBeach county.Doestheoutlierhaveanimpactontheresults?Findtheresidualforthatobser-

vationwithfit(ii)andinterpret.28

(c) Inthescatterplot,whyisthetoppoint,butnoteachofthetworightmostpoints,influ-

entialindeterminingtheregressionfit?Forthemodelfittedtoallthedata,useCook’s distance tohighlightthisinfluentialobservation.