\[\begin{array}{l}
\sum\limits_{i = 1}^{11} {{x_i}} = 13 + 27 + 11 + 15 + 9 + 16 + 18 + 11 + 6 + 8 + 11 = 145.\\
x\,\,\,\,\,6\,\,\,\,\,\,\,\,\,8\,\,\,\,\,\,\,\,\,\,9\,\,\,\,\,\,\,\,\,11\,\,\,\,\,\,\,13\,\,\,\,\,\,\,\,15\,\,\,\,\,\,\,\,\,\,\,16\,\,\,\,\,\,\,\,\,\,18\,\,\,\,\,\,\,\,\,27\\
n\,\,\,\,\,\,1\,\,\,\,\,\,\,\,\,\,1\,\,\,\,\,\,\,\,\,\,\,1\,\,\,\,\,\,\,\,\,\,3\,\,\,\,\,\,\,\,\,\,\,1\,\,\,\,\,\,\,\,\,\,1\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,1\,\,\,\,\,\,\,\,\,\,\,\,1\,\,\,\,\,\,\,\,\,\,\,\,\,\,1\\
\Rightarrow \overline x = \frac{{6.1 + 8.1 + 9.1 + 11.3 + 13.1 + 15.1 + 16 + 18.1 + 27.1}}{{11}} = \frac{{145}}{{11}}.\\
\sum\limits_{i = 1}^{11} {{{\left( {{x_i}} \right)}^2}} - {\left( {\sum\limits_{i = 1}^{11} {{x_i}} } \right)^2} = \left( {{6^2} + {8^2} + {9^2} + {{11}^2}.3 + {{15}^2} + {{16}^2} + {{18}^2} + {{27}^2}} \right) - {145^2} = 10012.
\end{array}\]
