Question

Calculate the mean deviation about the median of the following frequency distribution:

xi	5	7	9	11	13	15	17
fi	2	4	6	8	10	12	8

Answer 1

To find the mean deviation from the median, firstly let us calculate the median.

We know, N = 50

Median = (50)/2 = 25

So, the median Corresponding to 25 is 13

xi	fi	Cumulative Frequency	|di| = |xi – M| = |xi – 61|	fi |di|
5	2	2	8	16
7	4	6	6	24
9	6	12	4	24
11	8	20	2	16
13	10	30	0	0
15	12	42	2	24
17	8	50	4	32
	Total = 50			Total = 136

N = 50

MD = 1/n ∑ⁿ_i=1|d_i|

= 1/50 × 136

= 2.72

∴ The mean deviation is 2.72.