You have been hired to help elect a politician to office. You wish to know which form of advertising will result in the best outcome. You divide your participants into 3 groups , with 9 people in each group. Group one listens to positive ads only, group 2 listens to negative ads only and groups 3 listens to both positive and negative ads. You then record each person's response as a grade of between 0 to 100. Which one of the formulas below would you use to find your obtained value? X - u obtained ,3.Z X - X, 1.Z obtained X - H 21 obtained S Ox-X Vn -1 x - X2 5.0 8- 8 $ 2 n +n, 4.1 obtained + 6.0 8-8 Un -1 n, -1 n +n2 -2 \\ nn 2 O Formula 4 None of these formulas are useful to us Formula 6 Formula 5 Formula 2 O Formula 1 O Formula 3