Class interval |
Frequency |
Cumulative frequency |
15 - 25 |
8 |
8 |
25 - 35 |
10 |
18 |
35 - 45 |
15 |
33 |
45 - 55 |
25 |
58 (F) |
55 - 65 |
40 (f) |
98 |
65 - 75 |
20 |
48 |
75 - 85 |
15 |
133 |
85 - 95 |
7 |
140 |
|
N = 140 |
|
We have,
N = 140
\(\frac{N}{2}=\frac{140}{2}=70\)
The cumulative frequency is just greater than 98 then median class is 55-65 such that
l = 55, f = 40, F = 58, h = 65 – 55 = 10
Median = I + \(\frac{\frac{N}{2}-F}{f}\times h\)
\(=55+\frac{70-58}{40}\times 10\)
\(=55+\frac{12}{40}\times 10\)
\(=55+3=58\)
Therefore,
Median = 58