2012-II-29

16-06-2021 app.cch No Comments

Ans: B
The mean

\overset{―}{x}

$\begin{array}{cl} = & \frac{2 \times 0 + 8 \times 1 + 4 \times 2 + 6 \times 3 + 2 \times 4}{2 + 8 + 4 + 6 + 2} \\ = & \frac{21}{11} \end{array}$

The standard deviation

$\begin{array}{cl} = & \sqrt{\frac{2 (0 - \overset{―}{x})^{2} + \dots + 2 (4 - \overset{―}{x})^{2}}{22}} \\ = & 1.16 \end{array}$

2012, HKDSE-MATH, Paper 2 Statistics