1. Calculate Mean deviation, Coefficient of M.D. from the following grouped data

X	Frequency
0	1
1	5
2	10
3	6
4	3

Solution:
Mean deviation :

`x` `(1)`	`f` `(2)`	`f*x` `(3)=(2)xx(1)`	`|x-bar x|=|x-2.2|` `(4)`	`f*|x-bar x|` `(5)=(2)xx(4)`
0	1	0	2.2	2.2
1	5	5	1.2	6
2	10	20	0.2	2
3	6	18	0.8	4.8
4	3	12	1.8	5.4
---	---	---	---	---
--	`n=25`	`sum f*x=55`	--	`sum f*|x-bar x|=20.4`

Mean `bar x=(sum f x)/n`

`=55/25`

`=2.2`

Mean deviation of Mean
`delta bar x = (sum f*|x - bar x|)/n`

`delta bar x = 20.4/25`

`delta bar x = 0.816`


Coefficient of Mean deviation `=(delta bar x)/(bar x)`

`=0.816/2.2`

`=0.3709`

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