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Question
The following table shows the cumulative frequency distribution of marks of 800 students in an examination:
| Marks | Number of students |
| Below 10 | 10 |
| Below 20 | 50 |
| Below 30 | 130 |
| Below 40 | 270 |
| Below 50 | 440 |
| Below 60 | 570 |
| Below 70 | 670 |
| Below 80 | 740 |
| Below 90 | 780 |
| Below 100 | 800 |
Construct a frequency distribution table for the data above.
Solution
| Marks | Number of students | C.I. | No. of students |
| Below 10 | 10 | 0 – 10 | 10 |
| Below 20 | 50 | 10 – 20 | 50 – 10 = 40 |
| Below 30 | 130 | 20 – 30 | 130 – 50 = 80 |
| Below 40 | 270 | 30 – 40 | 270 – 130 = 140 |
| Below 50 | 440 | 40 – 50 | 440 – 270 = 170 |
| Below 60 | 570 | 50 – 60 | 570 – 440 = 130 |
| Below 70 | 670 | 60 – 70 | 670 – 570 = 100 |
| Below 80 | 740 | 70 – 80 | 740 – 670 = 70 |
| Below 90 | 780 | 80 – 90 | 780 – 740 = 40 |
| Below 100 | 800 | 90 – 100 |
800 – 780 = 20 |
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