Question 21
EasyOriginal questionA school recorded how long 50 students spent on homework one evening.
| Time (minutes) | Number of students |
|---|---|
| 0–20 | 7 |
| 20–40 | 11 |
| 40–60 | 16 |
| 60–80 | 10 |
| 80–100 | 6 |
In the homework-time table, which class contains the median?
Show the answer and explanation
CorrectNot quiteAnswer B
Correct answer: B
Explanation
, so .
Cumulative frequencies: 7, 18, 34, 44, 50.
The first cumulative frequency that reaches 25 is 34, which belongs to 40–60.
Worth noting
The median class is found from the cumulative frequency, not by picking the middle row or the row with the largest frequency (here those happen to coincide, but they often do not).
- Concept
- Locating the median class with cumulative frequency
- Typical timeTypical
- 40 s
- Your timeYours
- —
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