参考公式:
样本数据\[{x_1},{x_2}, \cdots ,{x_n}\]的方差\[{s^2} = \frac{1}{n}\sum\limits_{i = 1}^n {{{\left( {{x_i} - \overline x } \right)}^2}} \],其中\[\overline x = \frac{1}{n}\sum\limits_{i = 1}^n {{x_i}} \].
棱柱的体积$V = Sh$,其中$S$是棱柱的底面积,$h$是高.
棱锥的体积$V = \frac{1}{3}Sh$,其中S是棱锥的底面积,h为高.