Mean x = \(\frac{\sum x}{n}\) \( = \frac{5 + 4 + 3 + 2 + 1}{5}\) \( = \frac{15}{5}\) = 3 \(\begin{array}{c|c} x & d = x - 3 & d^2 \\ \hline 5 & 2 & 4 \\ 4 & 1 & 1 \\ 3 & 0 & 0 \\ 2 & -1 & 1 \\ 1 & -2 & 4 \\ \hline & & \sum d^2 + 10 \end{array}\) Hence, standard deviation; \( = \sqrt{\frac{\sum d^2}{n}} = \sqrt{\frac{10}{5}}\) \( = \sqrt{2}\)