The time taken by 70 students to solve a puzzle is recorded in the following table. Find the median class.
| Time (in minutes) | 0-5 | 5-10 | 10-15 | 15-20 | 20-25 | 25-30 | 30-35 |
|---|---|---|---|---|---|---|---|
| No. of students | 13 | 5 | 18 | 24 | 8 | 1 | 1 |
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 10-15
The median is the value of the middle observation. With \(n=70\), the middle lies at the \(\frac{n}{2}=35\)th student, so the median class is the first class whose cumulative frequency reaches 35.
Cumulative frequencies:
0-5: 13
5-10: \(13+5=18\)
10-15: \(18+18=36\), the first to reach 35
So the 35th student falls in the class 10-15.