1. Supposeyouwanttoestimatethelevelsofdioxin(achemicalassociatedwithcancer)incommerciallycaughtwildsalmon.Whichofthefollowingsamplingapproacheswouldgiveyouanunbiasedestimateofthedioxinlevels?(Theremaybemorethanonecorrectanswer.Theremayalsobenocorrectanswer.)

A. Fromaregistryofcommercialfishingboats,firstrandomlyselect10boatsandthentakesamplesfrom20randomlyselectedfishfromeachvessel.*

B. Fromaregistryofcommercialfishingboats,firstrandomlyselect1boatandthentakesamplesfrom20randomlyselectedfishfromtheselectedvessel.*

C.Takesamplesfrom100randomlyselectedsalmonfromthefirstcommercialfishingvesselthatreturnstotheBallarddocksattheendoftheseason.

(*Assume the registry includes all fishing boats)

2. Supposeyouwantedtoestimatethelevelsofdioxinincommerciallycaughtwildsalmon.Betweensamplingapproaches A and Binquestion21wouldgiveyouthemostprecise(leastvariable)estimateofdioxinlevels, or will the two estimates be equally precise?

3. Ifrandomlyselectedindividualsfromapopulationarecontactedandaskedtoparticipateinastudy,andifthosewhorefusearereplacedbyrandomlyselectedindividualswhoagreetoparticipate,shouldthefinalsamplebeconsideredarandomsubsetoftheoriginalpopulation?Explain.