Question

The standard deviation of $5$ scores $1,2,3,4,5$ is $\sqrt{a}$. The value of '$a$ ' is

• A. 2
• B. 3
• C. 5
• D. 1

Answer 1

Answer: (A)

Mean $(\bar{x})=\frac{1+2+3+4+5}{5}=3$
S. $D=\sigma =\sqrt{\frac{1}{5}(1+4+9+16+25)-9}$
$=\sqrt{11-9}=\sqrt{2}$