UPSC NDA Math Model Paper 8

Given data is 2, 9, 9, 3, 6, 9, 4
⇒ n = 7
Mean x=

2+9+9+3+6+9+4

7

⇒x=6
Mean deviation =

1

n

∑|x−x|
⇒ Mean deviation =

1

7

(|2−6|+|9−6|+|9−6|+|3−6| +|6−6|+|9−6+|4−6|)
⇒ Mean deviation = 2.57
Hence, the mean deviation of the data 2, 9, 9, 3, 6, 9, 4 is 2.57