Question -
Answer -
Let us make the tableof the given data and append other columns after calculations.
| Marks | Number of Girls fi | Cumulative frequency (c.f.) | Mid – points xi | |xi – Med| | fi|xi – Med| |
| 0 – 10 | 6 | 6 | 5 | 22.85 | 137.1 |
| 10 – 20 | 8 | 14 | 15 | 12.85 | 102.8 |
| 20 – 30 | 14 | 28 | 25 | 2.85 | 39.9 |
| 30 – 40 | 16 | 44 | 35 | 7.15 | 114.4 |
| 40 – 50 | 4 | 48 | 45 | 17.15 | 68.6 |
| 50 – 60 | 2 | 50 | 55 | 27.15 | 54.3 |
| 50 | | | | 517.1 |
The class intervalcontaining Nth/2 or 25th item is 20-30
So, 20-30 is themedian class.
Then,
Median = l + (((N/2) –c)/f) × h
Where, l = 20, c = 14,f = 14, h = 10 and n = 50
Median = 20 + (((25 –14))/14) × 10
= 20 + 7.85
= 27.85
