Question

Find the mean wages from the following data (Use assumed mean method).
Wages 800 820 860 900 920 980 1000
No. of workers 7 14 19 25 20 10 5

Answer 1

N=7+14+19+25+20+10+5=100
fx=800×7=5600
820×14=11480
860×19=16340
900×25=22500
920×20=18400
980×10=9800
1000×5=+5000
= 99120
mean=99120/100=991.2

Answer 2

Let the assumed mean be A = 900.

Calculation of Mean

Wage (in Rs)

x

i

No. of workers

f

i

d

i

=x

i

−A=x

i

−900

f

i

d

i

800 7 −100 −700

820 14 −80 1120

860 19 −40 −720

900 25 0 0

920 20 20 400

980 10 80 800

1000 5 100 500

N=∑f

i

=100

∑f

i

d

i

=−880

We have,

N=100,∑f

i

d

i

=−880 and A=900

∴Mean

X

=A+

N

∑f

i

d

i

⇒Mean

X

=900+

100

−880

=900−8.8=891.2

Hence, mean wage = Rs. 891.2.