Chapter 1 Chemistry and the Scientific Method - Problems - Page 35: 26

$2.32\%$

\begin{align*}\text{percentage error}&=\frac{\text{average value}-\text{true value}}{\text{true value}}\cdot 100\\ &=\frac{352\text{ m}\cdot\text{s}^{-1}-344\text{ m}\cdot\text{s}^{-1}}{344\text{ m}\cdot\text{s}^{-1}}\cdot 100\\ &=2.32\%\end{align*}