>>407
E(X) =ΣXi/n = 9.72
s^2 = Σ(Xi-E(X))^2/(n-1) = 3.70

E(X)-2.78*(s/√n)≦μ≦E(X)+2.78*(s/√n)
9.72-2.39≦μ≦9.72+2.39