Mean Height
1. **Stating the problem:** We are given a frequency polygon representing heights of members in a netball club. Our task is to estimate the mean height to 1 decimal place.
2. **Identify the heights (midpoints) and their frequencies from the graph:**
- Height (cm): 125, 150, 175, 200, 225
- Frequency: 9, 17, 18, 11, 8
3. **Calculate the weighted sum of heights multiplied by their frequencies:**
$$ \text{Sum} = 125 \times 9 + 150 \times 17 + 175 \times 18 + 200 \times 11 + 225 \times 8 $$
Calculate each term:
$$ 125 \times 9 = 1125 $$
$$ 150 \times 17 = 2550 $$
$$ 175 \times 18 = 3150 $$
$$ 200 \times 11 = 2200 $$
$$ 225 \times 8 = 1800 $$
4. **Add them up:**
$$ 1125 + 2550 + 3150 + 2200 + 1800 = 10825 $$
5. **Calculate the total frequency:**
$$ 9 + 17 + 18 + 11 + 8 = 63 $$
6. **Calculate the mean height estimate:**
$$ \text{Mean} = \frac{10825}{63} \approx 171.8254 $$
7. **Round to 1 decimal place:**
$$ 171.8 $$
**Final answer:** The estimated mean height is **171.8 cm**.