Question

20. Find the mean of the following frequency distribution using step-
deviation method:
Class:-
0-10
10-20
20-30
30-40
40-50
Frequency:-
7
10
15
8
10​

Answer 1

interval X No. of employees

F d=

i

X−A

Fd

4-8 6 5 -1 -5

8-12 10=A 10 0 0

12-16 14 15 1 15

16-20 18 20 2 40

ΣF=50 ΣFd=50

Mean = A+

Σf

Σfd

×i=10+(

50

50

×4)=10+4=14

D) 14

How satisfied are you with the