Question
The test marks of 80 students are recorded in the grouped frequency table below.
[6 marks]
| Mark (m) | Frequency |
|---|---|
| 0 < m ≤ 20 | 4 |
| 20 < m ≤ 40 | 10 |
| 40 < m ≤ 60 | 22 |
| 60 < m ≤ 80 | 30 |
| 80 < m ≤ 100 | 14 |
(a)Complete a cumulative frequency table for these marks.
(b)Use your cumulative frequencies to estimate the median mark.
(c)Estimate the lower quartile, the upper quartile and hence the interquartile range.
(d)Estimate how many students scored more than 70 marks.
This question has 4 parts. You don't have to get them all — each part you answer earns its own marks. Write them as (a) … ; (b) … , or just send the one part you worked out.
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