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Question
The following table gives the height of trees:
| Height | No. of trees |
| Less than 7 Less than 14 Less than 21 Less than 28 Less than 35 Less than 42 Less than 49 Less than 56 |
26 57 92 134 216 287 341 360 |
Draw 'less than' ogive and 'more than' ogive.
Solution
Consider the following table.
| Height (less than) | Height-class | No. of trees | Cumulative frequency | Suitable points |
| 7 | 0-7 | 26 | 26 | (7, 26) |
| 14 | 7-14 | 31 | 57 | (14, 57) |
| 21 | 14-21 | 35 | 92 | (21, 92) |
| 28 | 21-28 | 42 | 134 | (28, 134) |
| 35 | 28-35 | 82 | 216 | (35, 216) |
| 42 | 35-42 | 71 | 287 | (42, 287) |
| 49 | 42-49 | 54 | 341 | (49, 341) |
| 56 | 49-56 | 19 | 360 | (56, 360) |
Now, draw the less than ogive using suitable points.
Now, prepare the cumulative frequency table for more than series.
| Height | No. of trees | Height (more than) | Cumulative frequency | Suitable points |
| 0-7 | 26 | 0 | 360 | (0, 360) |
| 7-14 | 31 | 7 | 334 | (7, 334) |
| 14-21 | 35 | 14 | 303 | (14, 303) |
| 21-28 | 42 | 21 | 268 | (21, 268) |
| 28-35 | 82 | 28 | 226 | (28, 226) |
| 35-42 | 71 | 35 | 144 | (35, 144) |
| 42-49 | 54 | 42 | 73 | (42, 73) |
| 49-56 | 19 | 49 | 54 | (49, 54) |
Now, draw the more than ogive using suitable points.
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