1. **Problem Statement:**
We have a frequency distribution table of Subjective Happiness scores for 200 students. We need to complete the missing columns: Real limits, Median, Frequency percentage, Cumulative frequency, and Cumulative frequency percentage.
2. **Step 1: Calculate Real Limits**
Real limits are the boundaries of each class interval. For example, for class 120-124, the real limits are 119.5 to 124.5 (subtract 0.5 from lower limit and add 0.5 to upper limit).
3. **Step 2: Calculate Median of each class**
Median is the midpoint of each class interval, calculated as $$\text{Median} = \frac{\text{Lower limit} + \text{Upper limit}}{2}$$.
4. **Step 3: Calculate Frequency Percentage**
Frequency percentage for each class is $$\frac{\text{Frequency}}{N} \times 100 = \frac{\text{Frequency}}{200} \times 100$$.
5. **Step 4: Calculate Cumulative Frequency**
Cumulative frequency is the running total of frequencies from the first class up to the current class.
6. **Step 5: Calculate Cumulative Frequency Percentage**
Cumulative frequency percentage is $$\frac{\text{Cumulative frequency}}{N} \times 100$$.
7. **Step 6: Complete the table:**
| Class | Real limits | Median | Frequency | Frequency % | Cumulative Frequency | Cumulative Frequency % |
|-------|-------------|--------|-----------|-------------|----------------------|------------------------|
|120-124|119.5-124.5 |122 |8 |$\frac{8}{200} \times 100=4$|200|100|
|115-119|114.5-119.5 |117 |12 |6 |192 |96 |
|110-114|109.5-114.5 |112 |25 |12.5 |180 |90 |
|105-109|104.5-109.5 |107 |33 |16.5 |155 |77.5 |
|100-104|99.5-104.5 |102 |98 |49 |122 |61 |
|95-99 |94.5-99.5 |97 |18 |9 |24 |12 |
|90-94 |89.5-94.5 |92 |4 |2 |6 |3 |
|85-89 |84.5-89.5 |87 |1 |0.5 |2 |1 |
|80-84 |79.5-84.5 |82 |1 |0.5 |1 |0.5 |
(Note: Cumulative frequencies and percentages are calculated from bottom to top to match the descending order of classes.)
8. **Step 7: Calculate Percentile 85 score**
Percentile 85 means the score below which 85% of the data fall.
Formula for percentile position:
$$L = \text{Lower real limit of percentile class}$$
$$N = 200$$
$$CF = \text{Cumulative frequency before percentile class}$$
$$f = \text{Frequency of percentile class}$$
$$P = 85$$
$$\text{Percentile} = L + \left(\frac{P \times N/100 - CF}{f}\right) \times \text{class width}$$
9. **Step 8: Identify percentile class**
From cumulative frequency percentages, 85% lies between 77.5% and 90%, so percentile class is 110-114.
10. **Step 9: Calculate values:**
$$L = 109.5$$
$$CF = 122$$ (cumulative frequency before 110-114)
$$f = 25$$
$$\text{class width} = 5$$
11. **Step 10: Calculate percentile 85 score:**
$$\text{Percentile 85} = 109.5 + \left(\frac{0.85 \times 200 - 122}{25}\right) \times 5 = 109.5 + \left(\frac{170 - 122}{25}\right) \times 5 = 109.5 + \left(\frac{48}{25}\right) \times 5 = 109.5 + 1.92 \times 5 = 109.5 + 9.6 = 119.1$$
**Final answer:** The score at the 85th percentile is approximately **119.1**.
Percentile Rank 39154F
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