Question

Find the missing frequencies f; and f, in table given below; it is being given that the mean of the
given frequency distribution is 50.
Class
0-20 20-40 40-60 60-80 80-100 Total
Frequency 17
fi
32
f2
19
120​

Answer 1

Answer:

the best of luck to you and your family a very nice of you and your

Answer 2

Answer:

0−20 10 17 170

20−40 30 f

1

30f

1

40−60 50 32 1600

60−80 70 f

2

70f

2

80−100 90 19 1710

∑f

i

=f

1

+f

2

+68 ∑f

i

x

i

=3480+30f

1

+70f

2

∑f

i

=120 [ Given ]

∑f

i

=f

1

+f

2

+68

120=f

1

+f

2

+68

∴ f

1

+f

2

=52

⇒ f

1

=52−f

2

---- ( 1 )

⇒ Mean(

x

)=

∑f

i

∑f

i

x

i

⇒ 50=

120

3480+30f

1

+70f

2

⇒ 6000=3480+30(52−f

2

)+70f

2

[ From ( 1 ) ]

⇒ 2520=1560−30f

2

+70f

2

⇒ 40f

2

=960

∴ f

2

=24

Substituting value of f

2

in ( 1 )

f

1

=52−24=28

∴ f

1

=28,f

2

=24