The arithmetic mean of marks in Mathematics for four divisions A, B, C and D were 80, 75, 70 and 72…
The arithmetic mean of marks in Mathematics for four divisions A, B, C and D were 80, 75, 70 and 72 respectively. Their standard deviations were $12,6,8$ and and 10 respectively. Then, division has more uniformity.
D
B
C
A
Solution
$\begin{aligned}
& \text { We know that C.V. }=\frac{\text { Standard Deviation }}{\text { Mean }} \\
& \therefore(\text { C.V. })_A=\frac{12}{18}=0.15 \text { and }(\text { C.V. })_B=\frac{6}{75}=0.08 \\
& (\text { C.V. })_C=\frac{8}{70}=0.11 \text { and }(\text { C.V. })_D=\frac{10}{72}=0.14
\end{aligned}$
C.V. is the least for division B.
