1. **State the problem:** We need to estimate the mean distance jumped by the group of students using mid-interval values.
2. **Data given:**
- Distance intervals (cm): 0–80, 80–160, 160–240, 240–320, 320–400
- Number of students: 0, 2, 7, 12, 3
3. **Find mid-interval values:**
- Midpoint of 0–80 = $\frac{0 + 80}{2} = 40$
- Midpoint of 80–160 = $\frac{80 + 160}{2} = 120$
- Midpoint of 160–240 = $\frac{160 + 240}{2} = 200$
- Midpoint of 240–320 = $\frac{240 + 320}{2} = 280$
- Midpoint of 320–400 = $\frac{320 + 400}{2} = 360$
4. **Calculate total distance jumped:**
$$\text{Total distance} = (0 \times 40) + (2 \times 120) + (7 \times 200) + (12 \times 280) + (3 \times 360)$$
$$= 0 + 240 + 1400 + 3360 + 1080 = 6080$$
5. **Calculate total number of students:**
$$0 + 2 + 7 + 12 + 3 = 24$$
6. **Calculate mean distance jumped:**
$$\text{Mean} = \frac{\text{Total distance}}{\text{Total students}} = \frac{6080}{24}$$
7. **Simplify fraction:**
$$\frac{6080}{24} = \frac{\cancel{6080}^{253} \times 24}{\cancel{24}^{1} \times 24} = 253.33...$$
8. **Final answer:**
The estimated mean distance jumped is approximately **253 cm** (to the nearest centimetre).
Mean Jump Distance D41B9B
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