Sum of squares between samples is given by

A. $${\left( {{{\overline {\text{X}} }_1} + \overline {\text{X}} } \right)^2} + {\left( {{{\overline {\text{X}} }_2} - \overline{\overline {\text{X}}} } \right)^2} + .\,.\,.\,.$$

B. $${\left( {{{\overline {\text{X}} }_1} + \overline{\overline {\text{X}}} } \right)^2} + {\left( {{{\overline {\text{X}} }_2} - \overline {\text{X}} } \right)^{2 + }} + .\,.\,.\,.$$

C. $${\left( {{{\overline{\overline {\text{X}}} }_1} + \overline {\text{X}} } \right)^2} + {\left( {{{\overline {\text{X}} }_2} - \overline{\overline {\text{X}}} } \right)^{2 + }} + .\,.\,.\,.$$

D. $${\left( {{{\overline {\text{X}} }_1} + \overline{\overline {\text{X}}} } \right)^2} + {\left( {{{\overline {\text{X}} }_2} - \overline{\overline {\text{X}}} } \right)^2} + .\,.\,.\,.$$

Answer: Option D