18. the following data were obtained from an independent-measures study comparing three treatment conditions. treatment i ii iii 4 3 8 n = 12 3 1 4 g = 48 5 3 6 σx2 = 238 4 1 6 m = 4 m = 2 m = 6 t = 16 t = 8 t = 24 ss = 2 ss = 4 ss = 8 a. calculate the sample variance for each of the three samples. b. use an anova with α = .05 to determine whether there are any significant differences among the three treatment means.