1 S ta tis tic a l S tu d ie s a n d C o n su lt in g

33

1 S ta tis tic a l S tu d ie s a n d C o n su lt in g

1.1

E x p e rie n c e

•Knowledgeandskilloftheclientandtheconsultant

•Goalsoftheproject“HowshouldIinterpretthisoutput?”“Areviewerhascriticizedthefollowing:...HowcanIjustifymyapproach?”“IhavebeentoldtodoaConjointAnalysis.Whichprogramdoesthisforme?”“Ihavehereaninterestingdataset.Iwouldliketoapplymultivariatemethods.”

34

Roles:Statisticianis

•consultantwithalimitedtask(limitedliability)

•responsibleforadequatestatisticalanalysisofthedata

•partnerintheproject,fromplanningtoreporting/article

35 .1

cCommunication

•Whoposesthe(scientific)problem,andtowhomshouldtheanswerbetargeted?Whateffortwillthetargetedpersonsmaketounderstandtheanswer?

−→Typeofanswer,approachesthatcanbeunderstood.

•Whatknowledgedothetargetedpersons–thespecialists–thestatisticianshave?

•Howmucheffortcanbeinvested?(Money,time,energy)

36

Criticalpoints.Atthebeginningclarify:

•theproblem(“scientific”question).Informalquestionsareok.attheoutset,butmustbemadeprecise!

−→leadstomethodology=modelsandprocedures

•structureofthedata:Howhave/willtheybegenerated?Searchforgroupings–blocks,–”main/subplot”/”within/betweensubjects”–”closeness”inspaceortime.

37 .1

eWhyisdatastructureimportant?Statistics=model+estimationofparametersestimationwithoutindicationofprecisionismeaningless−→”standarderror”−→confidenceintervalortest.

Determinationofs.e.needsindependentobservations(oragoodmodelforthedependencies)If(positive)correlationsamongobservationsareneglected,

−→s.e.willbeunder-estimated

−→tooshortconfidenceintervalsor”liberaltests”(=wrong!)

Lookforindependentgroupsofobservations!Doanyanalysisyoulike,asforindividualobservations,thenusebootstrapovergroupstogetprecision.