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Differential misclassificationbias Non-differential misclassificationbias

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Question1.;Selectionbiasismostlikelytooccurinwhichtypeofstudy?Answer;Prospectivecohortstudies;Retrospectivecohortstudies;Casecontrolstudies;Bothretrospectivecohortandcasecontrolstudies.;2points;Question2.;Acasecontrolstudyisbeingconductedwhere10%ofthecasesandcontrolsactuallyhadthe;exposureofinterest.However,whenaskedabouttheexposure,only7%ofeachgrouprecalledthe;exposurecorrectly.Thisinaccuracy,representedequallybetweencasesandcontrols,couldbecalled;Answer;Differentialmisclassificationbias;Nondifferentialmisclassificationbias;Surveillancebias;Selectionbias.;2points;Question3.;Whenassessingtheresultsofastudy,whatarethepossibleexplanationsfortheobservedresults?;Answer;Theobservedresultsmaybeduetochance(i.e.,randomerror);Theobservedresultsmaybetrue;Theobservedresultsmaybeduetobias;Theobservedresultsmaybeduetoconfounding;The3rdand4thanswersonly;The1st,3rd,and4thanswersonly;Alloftheabove.;2points;Question4.;IfastudyfailstodetectasignificantdifferencebetweentreatmentAandtreatmentBwheninfact;thetreatmentsdodiffer,thefollowingtypeoferrorhasoccurred.Answer;TypeIerror;TypeIIerror;Treatmentdiscriminationerror;Differencetestingerror.;2points;Question5.;Controlsareneededinacasecontrolstudytoevaluatewhetherthefrequencyofafactororpast;exposureamongthecasesisdifferentfromthatamongcomparablepersonswhodonothavethe;diseaseunderinvestigation.AnswerTrueFalse;2points;Question6.;Controlledclinicaltrialsenableresearchersto:Answer;Deriveknowledgeabouttheoriginsofadisease;Controlthelevelofexposuretoatreatment;Moreaccuratelyidentifycauseandeffect;Alloftheabove.;2points;Question7.;Acasecontrolstudywasconductedtoidentifyriskfactorsforthecommoncold.Livingwith;childrenundertheageof10wasoneoftheriskfactorsevaluated.Theoddsratioforthisassociation;was9.0,andthe95%confidenceintervalrangedfrom1.2to85.Whichofthefollowingstatementsis;trueaboutthisassociation?Answer;Peoplewholivedwithachildundertheageof10had9timestheriskofgettingacoldcom;ThePvaluewasgreaterthan0.05.;ThePvaluewaslessthan0.05.;Theassociationwasstatisticallysignificant.;Thetruestrengthofassociationcouldbeestimatedmorepreciselyifthestudywererepeat;The1stand2ndanswersonly;The1stand3rdanswersonly;The1st,3rd,4th,and5thanswersonly;The1st,2nd,and5thanswersonly.;2points;Question8.;Whatsourcescanbeusedtoidentifycontrolsforacasecontrolstudy?Answer;Generalpopulation;Hospital/clinicpatients;Friendsandrelatives;Alloftheabove.;2points;Question9.;Whenassessingapositiverelationshipbetweenalcoholconsumptionandoralcancerusingacase;controlstudy,increasingthesamplesizeofthestudywillresultinwhichofthefollowing? Answer;AlowerPvalue;Agreateroddsratio;Asmaller95%confidenceinterval;Ahigherdiseaseprevalence;The1stand3rdanswersonly;The2ndand4thanswersonly;The1st,2nd,and3rdanswersonly;Alloftheabove;Noneoftheabove.;2points;Question10.;Asouthwesternstatepassedalawin1988makingitillegaltodrivewithoutwearingaseatbelt.To;determinewhetherthelawhadmadeadifferenceintermsofmortality,aresearcherinthestate;healthdepartmentcompileddataondeathsduetovehiclecrashesinthe5yearsbefore1988andin;the5yearsafter1988.Whattypeofstudyisthis?Answer;Randomizedcontrolledtrial;Concurrentcohortstudy;Retrospectivecohortstudy;Casecontrolstudy;Nestedcasecontrolstudy;Crosssectionalstudy;Ecologicstudy.;2points;Question11.;Anysystematicerrorinthedesignorconductofastudythatresultsinanincorrectestimateofan;exposure'seffectontheriskofdiseaseiscalled:Answer;Confounding;Bias;Stratification;Effectmodification.;2points;Question12.;Foravariabletobeaconfounder,itmustbe:Answer;Associatedwiththedisease(outcome)understudy;Associatedwiththeriskfactor(exposure)understudy;Bothoftheabove;Neitheroftheabove.;Question13.;2points;Whichoneofthefollowingstatementsbestdescribesalimitationofcrosssectionalstudies? Answer;Noinformationonindividuals;Uncleartemporalrelationshipbetweenexposureanddisease;Nocomparisongroup.;2points;Question14.;Theprimarydifferencebetweenanexperimentalandobservationalstudyis:Answer;Theinvestigatoris"blinded"(preventedfromknowingthesubjects'trueexposurestatusu;observationalstudy.;Theinvestigatorcontrolsthesubject'sexposureinanexperimentalstudybutnotinanobs;Theinvestigatorcontrolsthesubject'soutcomeinanexperimentalstudybutnotinanobse;Experimentalstudiesareconductedwithanimals,observationalstudiesareconductedwith.;2points;Question15.;Overthepast2years,effortsweremadetoidentifyanddeterminethemortalityandmorbidity;experienceofseveralthousandmilitarypersonnelwhowerestationedinthePersianGulfand;elsewhereinEuropein1991.Whattypeofstudyisthis?Answer;Casecontrolstudy;Prospectivecohortstudy;Retrospectivecohortstudy;Randomizedtrial.;2points;Question16.;Acrosssectionalstudyoftherelationshipbetweenbloodtypeandtheriskofcataractswillproduce;misleadingresultsbecauseyoucannottellthecorrecttemporalrelationshipbetweentheexposure;(bloodtype)anddisease(cataracts).AnswerTrueFalse;2points;Question17.;Researcherscollectedbaselineinformationonoralcontraceptiveusefromagroupoffemalecollege;seniorsfromalargeuniversity.Eachyearforthenext20years,thewomenwerefolloweduponto;determinewhetherornottheparticipantshaddevelopedanyofseveralconditions.Whattypeof;studyisthis?Answer;Casecontrolstudy;Prospectivecohortstudy;Retrospectivecohortstudy;Randomizedtrial;Crosssectionalstudy.;2points;Question18.;Thehealthyworkereffectisaformofwhattypeofbias?Answer;Selectionbias;Controlselectionbias;Interviewer/recordingbias;Surveillance,diagnostic,orreferralbias.;2points;Question19.;Whenchance,bias,andconfoundinghavebeenruledoutasalternativeexplanationsforan;association,wemayconcludethattheassociationiscausal.AnswerTrueFalse;2points;Question20.;Advantagesofacasecontroldesignincludeallthefollowingexcept:Answer;Itisappropriateforstudyingrarediseases.;Itisappropriateforstudyingrareexposures.;Theoddsratiocanprovideanestimateoftherelativerisk.;Multipleexposurescanbestudied.

 

Paper#15543 | Written in 18-Jul-2015

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