We conduct a research into sexual practices of high school students. We find that boys (n=345) and girls (n=125) have sex at slightly different ages. . Which of the ollowing formulas would you use to calculate the obtained value? X - H 2.1obtained X - u X - X, 1.Z obtained = ,3.Z obtained S Jn - 1 S , In + 2 4 1 obtained X - X2 5.0 8- 8 + 6.0 x-8 Ox-X n-1 n, -1 In +n2 - 2 \\ nn2 Formula 2 Formula 3 O Formula 5 None of these formulas are useful to us Formula 1 O Formula 6