Q268 / 270 · NDA 2022 (Phase 2) · Mathematics
Consider the following grouped frequency distribution :
$\begin{array}{|l|l|l|l|l|l|l|}
\hline \text { Class } & 0-10 & 10-20 & 20-30 & 30-40 & 40-50 & 50-60 \\
\hline \text { Frequency } & 1 & 2 & 4 & 6 & 4 & 3 \\
\hline
\end{array}$
What is the median of the distribution?
- A$34$
- B$34.5$
- Correct answerC$35$
- D$35.5$
Solution
$\begin{array}{|l|c|c|c|c|c|c|}
\hline \text { Class } & 0-10 & 10-20 & 20-30 & 30-40 & 40-50 & 50-60 \\
\hline \text { fi } & 1 & 2 & 4 & 6 & 4 & 3 \\
\hline \text { C.F. } & 1 & 3 & 7 & 13 & 17 & 20 \\
\hline
\end{array}$
$\begin{aligned} & \frac{N}{2}=\frac{20}{2}=10 \\ & \therefore \quad \text { Median class }=30-40 \\ & \therefore \quad \text { Median }=l+\frac{\frac{N}{2}-C}{f} \times h . \\ & \mathrm{Me}=30+\frac{10-7}{6} \times 10 \\ & =30+5=35\end{aligned}$
Hence, the correct answer is option: 'C'.