Learners Performance
1. **Problem Statement:**
The school wants to analyze learners' performance based on the histogram data showing learners' scores and frequencies.
2. **Given Data:**
Class intervals (scores): 24.5-34.5, 34.5-44.5, 44.5-54.5, 54.5-64.5, 64.5-74.5, 74.5-84.5, 84.5-94.5
Frequencies (approximate): 13, 29, 12, 45, 85, 29, 12
3. **Step 1: Calculate the midpoint for each class interval**
Midpoint formula: $$\text{Midpoint} = \frac{\text{Lower boundary} + \text{Upper boundary}}{2}$$
- 24.5 to 34.5: $\frac{24.5 + 34.5}{2} = 29.5$
- 34.5 to 44.5: $\frac{34.5 + 44.5}{2} = 39.5$
- 44.5 to 54.5: $\frac{44.5 + 54.5}{2} = 49.5$
- 54.5 to 64.5: $\frac{54.5 + 64.5}{2} = 59.5$
- 64.5 to 74.5: $\frac{64.5 + 74.5}{2} = 69.5$
- 74.5 to 84.5: $\frac{74.5 + 84.5}{2} = 79.5$
- 84.5 to 94.5: $\frac{84.5 + 94.5}{2} = 89.5$
4. **Step 2: Calculate the total number of learners**
$$N = 13 + 29 + 12 + 45 + 85 + 29 + 12 = 225$$
5. **Step 3: Calculate the mean score**
Mean formula for grouped data:
$$\bar{x} = \frac{\sum f_i x_i}{N}$$
where $f_i$ is frequency and $x_i$ is midpoint.
Calculate $\sum f_i x_i$:
$$13 \times 29.5 = 383.5$$
$$29 \times 39.5 = 1145.5$$
$$12 \times 49.5 = 594$$
$$45 \times 59.5 = 2677.5$$
$$85 \times 69.5 = 5907.5$$
$$29 \times 79.5 = 2305.5$$
$$12 \times 89.5 = 1074$$
Sum:
$$383.5 + 1145.5 + 594 + 2677.5 + 5907.5 + 2305.5 + 1074 = 13987.5$$
Mean:
$$\bar{x} = \frac{13987.5}{225} \approx 62.17$$
6. **Step 4: Calculate the percentage of learners below the pass mark 55**
Pass mark 55 lies between 54.5 and 64.5 intervals.
Frequencies below 55 are for intervals:
- 24.5-34.5: 13
- 34.5-44.5: 29
- 44.5-54.5: 12
Total learners below 55:
$$13 + 29 + 12 = 54$$
Percentage below pass mark:
$$\frac{54}{225} \times 100 \approx 24\%$$
7. **Interpretation:**
- The mean score is approximately 62.17.
- About 24% of learners scored below the pass mark of 55.
If the previous mean score was lower than 62.17, this indicates an improvement in learners' performance.
**Final answers:**
- Mean score: $62.17$
- Percentage below pass mark: $24\%$