The mean deviation from the median of the following series is :

Serial number	1	2	3	4	5	6	7	8	9
Marks out of 100	68	49	32	21	54	38	59	66	41

Formula Used:

Mean Deviation about the median = \(\frac{\left[\sum |x_i– median|\right]}{N}\)

Here, 

x_i represents each value in the data set

N represents the number of data values

Calculation:

The above data in the descending order is: 68, 66, 59, 54, 49, 41, 38, 32, 21

which are 9 terms hence, the median is the 5^th term from either side,

Hence, the median of the given data is 49.

N = 9

⇒ Mean Deviation about the median = \(\frac{\left[\sum |x_i– 49|\right]}{9}\)

⇒ Mean Deviation = \(\frac{|68– 49|+|66– 49|+|59– 49|+|54– 49|+|49– 49|+|41– 49|+|38– 49|+|32– 49|+|21– 49|}{9}\)

⇒ Mean Deviation = \(\frac{19+17+10+5+0+8+11+17+28}{9}\)

⇒ Mean Deviation =\(\frac{115}{9}\)