1. Calculate Less than type Cumulative frequency table from the following grouped data
| Class | Frequency |
| 10 - 20 | 15 |
| 20 - 30 | 25 |
| 30 - 40 | 20 |
| 40 - 50 | 12 |
| 50 - 60 | 8 |
| 60 - 70 | 5 |
| 70 - 80 | 3 |
Solution:| Class | Frequency |
| 10 - 20 | 15 |
| 20 - 30 | 25 |
| 30 - 40 | 20 |
| 40 - 50 | 12 |
| 50 - 60 | 8 |
| 60 - 70 | 5 |
| 70 - 80 | 3 |
Less than cumulative frequency can be obtained by adding to the other frequencies.
| Class | Frequency | Less than type | Cumulative Frequency |
| 10 - 20 | 15 | Less than 20 | 15 |
| 20 - 30 | 25 | Less than 30 | 40 (= 15 + 25) |
| 30 - 40 | 20 | Less than 40 | 60 (= 40 + 20) |
| 40 - 50 | 12 | Less than 50 | 72 (= 60 + 12) |
| 50 - 60 | 8 | Less than 60 | 80 (= 72 + 8) |
| 60 - 70 | 5 | Less than 70 | 85 (= 80 + 5) |
| 70 - 80 | 3 | Less than 80 | 88 (= 85 + 3) |
This material is intended as a summary. Use your textbook for detail explanation.
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