Chapter 2 - Methods for Describing Sets of Data - Exercises 2.44 - 2.47 - Learning the Mechanics - Page 50: 2.45e

$1089$

If $S=\displaystyle \sum x$ = sum of all the data items, then $ S^{2}=\left( \displaystyle \sum x\right)^{2}$ = the square of the sum of all the data items. \begin{align*} S&=3+8+4+5+3+4+6\\ &=33\\\\ S^{2}&=33^{2}=1089\end{align*}