UPSC NDA Math Model Paper 1

Arrange data in ascending order –
2, 3, 4, 6, 7, 9, 11
No. of observation n = 7 (odd)
Median will be (

n+1

2

) th term i.e. 4th term =6.
Mean deviation about their median M is given by M.D(M)=

xi−M|

n

Here, M=6
M.D(M)=

18

7

=2.57