Find the mean deviation and its coefficient about the mean of the following data. | Statistics | SciPiPupil

Question: Find the mean deviation about the mean for the following data:

Mark	0-10	10-20	20-30	30-40	40-50
Frequency	2	3	6	5	4

Solution:

Arranging data in a table,

Marks	Frequency (f)	Mid Value(x)	fx	|x-x̄|	f|x-x̄|
0-10	2	5	10	23	46
10-20	3	15	45	13	39
20-30	6	25	150	3	18
30-40	5	35	175	7	35
40-50	4	45	180	17	68
	N= 20		$\sum$fx = 560		$\sum$f|x-x̄| = 206

Now,

Mean (x̄) =$\dfrac{\sum fx}{N}$

$= \dfrac{560}{20}$

$= 28$

And,

Mean Deviation from Mean (M.D.) = $\dfrac{\sum f|x-x̄|}{N}$

$= \dfrac{206}{20}$

$= 10.30$

Also,

Coefficient of M.D. = $\dfrac{M.D.}{x̄}$

$= \dfrac{10.30}{20}$

$= 0.37$

Hence, the required mean deviation about the mean of the given data is 10.30 and coefficient of mean deviation is 0.37.

Related Notes and Solutions:

Here is the website link to the notes of Statistics of Class 10.

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