Opt-in Group: 55 total - 23 donors = 32 non-donors. Opt-out Group: 50 total - 41 donors = 9 non-donors. Neutral Group: 56 total - 44 donors = 12 non-donors. Sum the Totals for Each Row and Column: Total Organ Donors: 23 (Opt-in) + 41 (Opt-out) + 44 (Neutral) = 108. Total Not Organ Donors: 32 (Opt-in) + 9 (Opt-out) + 12 (Neutral) = 53. Total Participants: 55 (Opt-in) + 50 (Opt-out) + 56 (Neutral) = 161