Page 3 - Lesson Note MCT 2 53
P. 3
Answer: - calculation of median.
Marks (X) Frequency (f) Cumulative frequency (c. f)
0 – 10 08 08
10 – 20 14 22
20 – 30 34 56
30 – 40 12 68
40 – 50 14 82
50 – 60 03 85
60 – 70 02 87
70 - 80 13 100
= ∑ = 100
Median = ℎ ℎ
2
100
= = 50th data in the series.
2
Median class is 20 – 30
= 20, f = 34, c. f = 22, i = 10.
1
− .
Median = + 2 ×
1
50 − 22
= 20 + × 10
34
280
= 20 +
34
= 20 + 8.2353
= 28.2353
Ex: - Calculate median from the following data.
Mid-values 37.5 42.5 47.5 52.5 57.5
No of students 30 20 15 13 22
Answer: -
Mid-values Class interval (X) f C.F
37.5 35 – 40 30 30
42.5 40 – 45 20 50
47.5 45 – 50 15 65
52.5 50 – 55 13 78
57.5 55 - 60 22 100
