Question

Compute the median for the following data:

Marks	No. of students
Less than 10	0
Less than 30	10
Less than 50	25
Less than 70	43
Less than 90	65
Less than 110	87
Less than 130	96
Less than 150	100

Answer 1

Marks	No. of students	Class internal	Frequency	Cumulative frequency
Less than 10	0	0 – 10	0	0
Less than 30	10	10 – 30	10	10
Less than 50	25	30 – 50	15	25
Less than 70	43	50 – 70	18	43
Less than 90	65	70 – 90	22	65
Less than 110	87	90 – 110	22	87
Less than 130	96	110 – 130	9	96
Less than 150	100	130 – 150	4	100
			N = 100

We have N = 100

`N/2=100/2=50`

The commutative frequencies just greater than N/2 is 65 then median class is 70 – 90.

such that l = 70, f = 22, h = 90 – 70 = 20 and F = 43

Median `= l + (N/2 - F)/f xx h`

`=70 + (50 - 43)/22 xx 20`

`=70 + (7 xx 20)/22`

`=70 + 140/22`

= 70 + 6.36

= 76.36