Find the mean deviation about the mean for 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	50-60
Number Of Students	6	8	14	16	4	2

Solution:

Arranging data in a table,

Marks	Frequency (f)	Mid Value(x)	fx	|x-x̄|	f|x-x̄|
0-10	6	5	30	22	132
10-20	8	15	120	12	36
20-30	14	25	350	2	28
30-40	16	35	560	8	128
40-50	4	45	180	18	72
50-60	2	55	110	28	56
	N= 50		$\sum$fx = 1350		$\sum$f|x-x̄| = 512

Now,

Mean (x̄) =$\dfrac{\sum fx}{N}$

$= \dfrac{1350}{50}$

$= 27$

And,

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

$= \dfrac{512}{50}$

$= 10.24$

Hence, the required mean deviation about the mean of the given data is 10.24.

Related Notes and Solutions:

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

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