Question

The standard deviation (S.D) of the scores 1, 2, 3, 4, 5 is:

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

$Here,\overline{x}=\frac{1+2+3+4+5}{5}=3$
$\begin{array}{ccc}x& x-\overline{x}& (x-\overline{x}{)}^2\\ 1& -2& 4\\ 2& -1& 1\\ 3& 0& 0\\ 4& 1& 1\\ 5& 2& 4\end{array}\therefore \sum (x-\overline{x}{)}^2=10$

$\therefore S.D=\sigma =\sqrt{\frac{(x-\overline{x})}{N}}=\sqrt{\frac{10}{5}}=\sqrt{2}$