Here xi = 6, 7, 10, 12, 13, 4, 8, 12 ∴ Σ $x_i$ = 6 + 7 + 10 + 12 + 13 + 4 + 8 + 12 = 72; n = 8 ∴ Mean $(\overline{x})$ = $\frac{72}{8}$ = 9 Now, Sx2i= $(6)^2 + (7)^2 + (10)^2 + (12)^2$ + $(13)^2 + (4)^2 + (8)^2 + (12)^2$ = 36 + 49 + 100 + 144 + 169 + 16 + 64 + 144 = 722 ∴ Variance $(\sigma^2)$ = $\frac{n\Sigma x_i^2 - (\Sigma x_i)^2}{n^2}$ = $\frac{8\times 722 - (72)^2}{(8)^2}$ = $\frac{5776 - 5184}{64}$ = $\frac{592}{64}$ = 9.25