SamplesizecalculationsPleaseentertheTypeIerror(alpha)5.0%asapercentagebetween0and100Pleaseenterthenumberofsides:21foraone-sidedtest2foratwo-sidedtestPleasechoosethestudydesign:CohortstudyClinicaltrialCross-sectionalstudyCase-controlAuthors:MarkWoodward,TheGeorgeInstituteforInternationalHealthLesleyFrancis,MISConsultantsPtyLtd10.16000Samplesize(bothgroupscombined)11140TypeIerror5.0Sides2Power?%TochangethesevaluesreturntoStartRelativerisktobedetected0.86ResultsTotalGroup1Group2Samplesize1114055705570Power91.3%Minimumdetectablerelativerisk10.86Cohortandcross-sectionalstudiesandclinicaltrials:Samplesize,powerandminimumrelativeriskMaximumdetectablerelativerisk1ReturntostartPleaseentertheratioofthetwosamplesizes(group1/group2)Pleaseentertheestimatedproportioninthereferencegroup(group2)Pleaseenterthevaluesfortwoofthefollowingparameters,and?fortheparametertobecalculatedCase-controlstudies:samplesize,powerandminimumdetectablerisk130.0%Pleaseenterthevaluesfortwoofthefollowingparameters,and?fortheparametertobecalculatedSamplesize(bothgroupscombined)?TypeIerror5.0%Power80.0%Sides2TochangethesevaluesRelativerisktobedetected2.00returntoStartResultsTotalGroup1Group2Samplesize282141141Power80.0%Minimumdetectablerelativerisk12.00Maximumdetectablerelativerisk1ReturntostartPleaseentertheratioofcontrolstocasesPleaseentertheprevalenceoftheriskfactorCohortandcross-sectionalstudiesandclinicaltrialsPleaseindicateforwhichsituationcalculationsarerequired:DifferencesbetweenmeansDifferencebetweenmeans(Pairedttest)Relativeriskreturntostart14Samplesize?TypeIerror5.0%Power90%Sides2TochangethesevaluesMinimumdetectabledifference3.10returntoStartResultsSamplesize215Power90.0%Minimumdetectabledifference3.10Pairedcomparisons:Cohortandcross-sectionalstudiesandclinicaltrials:sample,sizepowerandminimumdifferenceReturntostartPleaseentertheestimatedstandarddeviationofthedifferencesPleaseenterthevaluesfortwoofthefollowingparameters,and?fortheparametertobecalculatedPairedcomparisons:Cohortandcross-sectionalstudiesandclinicaltrials:sample,sizepowerandminimumdifference10.35Samplesize(bothgroupscombined)?TypeIerror5.0%Power90%Sides2TochangethesevaluesMinimumdetectabledifference0.12returntoStartResultsTotalGroup1Group2Samplesize358179179Power90.0%Minimumdetectabledifference0.12ReturntostartPleaseentertheratioofthetwosamplesizes(group1/group2)Cohortandcross-sectionalstudiesandclinicaltrials:sample,sizepowerandminimumdifferencePleaseentertheestimatedstandarddeviationineachgroupPleaseenterthevaluesfortwoofthefollowingparameters,and?fortheparametertobecalculated