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Question
The following table shows the number of saplings planted by 30 students. Fill in the boxes and find the average number of saplings planted by each student.
| No. of saplings (Scores) xi |
No. of students (frequncy) fi |
fi x xi |
| 1 | 4 | 4 |
| 2 | 6 | `square` |
| 3 | 12 | `square` |
| 4 | 8 | `square` |
| N = `square` | ∑fixi = `square` |
Mean `bar "x"` = `square/"N"`
= `square/square`
= `square`
∴ The average number of trees planted `square`
Solution
| No. of saplings (Scores) xi |
No. of students (frequncy) fi |
fi×xi |
| 1 | 4 | 4 |
| 2 | 6 | = 2 x 6 = 12 |
| 3 | 12 | = 3 x 12 = 36 |
| 4 | 8 | = 4 x 8 = 32 |
| N = 30 | ∑fixi = 84 |
Mean `bar "x"` = `bb((sum f_ix_x))/"N"`
= `bb(84/30)`
= 2.8
∴ The average number of trees planted is 2.8.
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