UPSC CDS Math Statistics Questions

Here, N=40⇒

N

2

=20
Therefore, median class =7–8
Median =L+(

N 2 −F

f

)×h
Thus, the median of the age distribution is 8 years.
Hence, statement 1 is incorrect.
Number of children in the age group 6–9 years =7+9+12=28
Therefore, percentage of the children in the age group 6–9 years =

28

40

×100%=70%
Hence, statement 2 is correct.
Mode lies in the class interval 8–9 since its frequency is the highest.
Therefore, the modal age of the children is 8 years as the age 9 years is included in the interval 9–10.
Hence, statement 3 is correct.