Question

Pls do give me the answer for this. This is class 10 statistics.

Answer 1

ANSWER

Class f

1

Frequency x

i

Mid-values u

i

=

h

x

i

−A

f

i

u

i

0−20 17 10 −2 −34

20−40 f

1

30 −1 −f

1

40−60 32 50 0 0

60−80 f

2

70 1 −f

2

80−100 19 90 2 38

N= ∑f

i

=63+f

1

+f

2

∑f

i

u

i

=4−f

1

+f

2

We have,

N=∑f

i

=120 [Given]

⇒68+f

1

+f

2

=120

⇒f

1

+f

2

=52

Now,

Mean = 50

⇒A+h[

N

1

∑f

i

u

i

]=50

⇒50+20×[

120

4−f

1

+f

2

]=50

⇒

6

4−f

1

+f

2

=0

⇒4−f

1

+f

2

=0

⇒f

1

−f

2

=4

Solving equations (i) and (ii), we get f

1

= 28 and f

2

=24.

Answer 2

x = 21

Step-by-step explanation:

First find xi of all clsses . ( xi is the middle term of a class)

Then find fixi of each class and find the sum of fixi . It will be 4250+50x

Then take sum of fi i.e. 79+x

Divide fixi by fi i.e. 4250 + 50x / 79+x and equate it with the mean given ie 53

53 = 4250+50x / 79+x

53×79+x = 4250+50x

4187+53x = 4250+50x

53x-50x = 4250-4187

3x = 63

x= 21