Page 3 - Lesson Note MCT 2 54
P. 3
− .
Median = + 2 ×
1
25 − 16
= 20 + × 10
18
90
= 20 +
18
= 20 + 5 = 25
Calculation of median in case of un-equal class interval: -
When the class-intervals are un-equal, there is no need to make the
class intervals equal and the same formula would be applied to calculate
median.
EX: - From the following data obtain median.
Class interval 0 - 5 5 - 10 10 - 20 20 - 30 30 - 50 50 - 70 70 - 100
No of students 12 15 25 40 42 14 08
Answer: - calculation of median.
Class interval (X) No of students (F) Cumulative frequency (C.F)
0 – 5 12 12
5 – 10 15 27
10 – 20 25 52
20 – 30 40 92
30 – 50 42 134
50 – 70 14 148
70 - 100 08 156
= ∑ = 156
Median = ℎ ℎ
2
156
= = 78th data in the series.
2
Median class is 20 - 30
= 20 f =40, c. f = 52, i = 10.
1
− .
Median = + 2 ×
1
78 − 52
= 20 + × 10
40
