Q266 / 270 · NDA 2022 (Phase 2) · Mathematics
The mean and standard deviation (SD) of marks obtained by 50 students of a class in 4 subjects are given below:
$\begin{array}{|c|c|c|c|c|}
\hline \text { Subject } & \text { Mathematics } & \text { Physics } & \text { Chemistry } & \text { Biology } \\
\hline \begin{array}{c}
\text { Mean } \\
\text { Marks }
\end{array} & 40 & 28 & 38 & 36 \\
\hline \text { SD } & 15 & 12 & 14 & 16 \\
\hline
\end{array}$
Which one of the following subjects shows highest variability of marks?
- AMathematics
- BPhysics
- Correct answerCChemistry
- DBiology
Solution
C.V. of Mathematics $=\frac{15}{40} \times 100=37.5 \%$
C.V. of Physics $=\frac{12}{28} \times 100=42.86 \%$
C.V. of Chemistry $=\frac{14}{38} \times 100=36.84 \%$
C.V. of Biology $=\frac{16}{36} \times 100=44.44 \%$
Since C.V. of Biology is greatest, therefore, Biology have more variability.
Hence, the correct answer is option: 'C'.