Following are the marks obtained by 9 students in a mathematics test:

50, 69, 20, 33, 53, 39, 40, 65, 59

The mean deviation from the median is:

Given the marks obtained by 9 students in a mathematics test are 50, 69, 20, 33, 53, 39, 40, 65, 59

As number of students =9, which is odd.

So median will be = 5^th term.

Arranging these in ascending order, we get

20, 33, 39, 40, 50, 53, 59, 65, 69

So the 5^th term after arranging is 50,

So median is 50.

This can be written in table form as,

Hence Mean Deviation becomes,

Therefore, the mean deviation about the median of the marks of 9 subjects is 12.67