Explanation
Solution
1. Equation from Total Frequency
Summing all frequencies to 686:
180+f1+34+180+136+f2+50=686
2. Cumulative Frequency (CF) Table
| Class Interval |
Frequency (f) |
Cumulative Frequency (cf) |
| 10−20 |
180 |
180 |
| 20−30 |
f1 |
180+f1 |
| 30−40 |
34 |
214+f1 |
| 40−50 |
180 |
394+f1 |
| 50−60 |
136 |
530+f1 |
| 60−70 |
f2 |
530+f1+f2 |
| 70−80 |
50 |
580+f1+f2=686 |
3. Identifying Median Class
Since the median is 42.6, the Median Class is 40−50.
4. Applying the Median Formula
42.6=40+[180343−(214+f1)]×10
Since frequency must be an integer, we round f1 to 82.
5. Finding f2
Using Eq. 1:
Final Answer
The values are f1=82 and f2=24.