1. In a school nursery, the following were the heights of 60 tree seedlings after 3 months of germination (correct to the nearest cm).
|
Height in cm |
15-19 |
20-24 |
25-29 |
30-34 |
35-39 |
40-44 |
45-49 |
|
No of Seedlings |
6 |
10 |
13 |
15 |
9 |
5 |
2 |
| Class | n | x-A=d | f | fd |
| 15-19 | 17 | 6 | -90 | |
| 20-24 | 22 | -10 | 10 | |
| 25-29 | 27 | 13 | ||
| 30-34 | 32 | 0 | 15 | 0 |
| 35-39 | 37 | 5 | 9 | |
| 40-44 | 42 | 5 | 50 | |
| 45-49 | 47 | 2 | ||
| Σƒ= | Σƒd= |