<prompt> Relative risk can be obtained fromCase studyCoho studyCase control studyExperimental study  <response>: Strength of association in Coho study Strength of associationFormulaRelative risk Risk ratioRR Incidence among exposed Incidence among non exposed RR 1Positive association RR 1 No association RR 1Negative association Attributable riskAR Incidence among exposed-Incidence among non exposedIncidence among exposed x 100Population attributable risk PAR Incidence among total -Incidence among non exposedIncidence among total x 100Refer: K. Parks Textbook of Preventive and Social Medicine, 24th edition, pg no: 83, 93 