Score Statistics
1. **State the problem:** Given the scores and their frequencies:
Scores: $5, 6, 7, 8, 9$
Frequencies: $13, 22, 35, 26, 11$
We need to find the mean, median, mode, and range of the data.
2. **Calculate the mean:**
The mean is the weighted average of the scores:
$$\text{Mean} = \frac{\sum (\text{score} \times \text{frequency})}{\sum \text{frequency}}$$
Calculate numerator:
$$5 \times 13 = 65$$
$$6 \times 22 = 132$$
$$7 \times 35 = 245$$
$$8 \times 26 = 208$$
$$9 \times 11 = 99$$
Sum numerator:
$$65 + 132 + 245 + 208 + 99 = 749$$
Sum frequencies:
$$13 + 22 + 35 + 26 + 11 = 107$$
Mean:
$$\frac{749}{107} \approx 7.0$$
3. **Calculate the median:**
Total frequency is 107, so median position is at $\frac{107 + 1}{2} = 54$th value.
Cumulative frequencies:
- Up to score 5: 13
- Up to score 6: 13 + 22 = 35
- Up to score 7: 35 + 35 = 70
Since 54 is between 36 and 70, the median score is 7.
4. **Calculate the mode:**
The mode is the score with the highest frequency.
Frequencies: 13, 22, 35, 26, 11
Highest frequency is 35 at score 7.
Mode = 7
5. **Calculate the range:**
Range = highest score - lowest score = $9 - 5 = 4$
**Final answers:**
- Mean = 7.0
- Median = 7
- Mode = 7
- Range = 4