2.2. For the moment, ignore the matching. Construct a 2x2 table that relates tattooing/piercing to case/control status. Calculate the unmatched Odds Ratio for this association: Tattooing/piercing Yes No Case (HCV+) Control (HCV-) Odds Ratio = ad/bc = 1. The moR (matched Odds Ratio) was: 2. Why are these two estimates of the Odds Ratio different? a) The authors tried for 4:1 matching (256:64), but got only 227 controls. b) The authors made a mistake in their calculation. c) Breaking up the matching in a matched study moves the OR closer to 1.0. di The OR requires the rare disease assumption to be a valid estimate