Question

The S.D. of 7 scored 1, 2, 3, 4, 5, 6, 7 is

• A. 4
• B. 2
• C. $\sqrt{7}$
• D. none of these

Answer 1

The correct option is B 2

Given observation is, 1,2,3,4,5,6,7

Here $N=7,\sum x=28,\sum x^2=140$

$\therefore$ Required S.D $=\sqrt{\frac{\sum x^2}{N}-{\left(\frac{\sum x}{N}\right)}^2}=\sqrt{4}=2$