Question

solve this
..................​

Answer 1

The given data is shown as follows:

Class interval

0-10

10-20

20-30

30-40

40-50

50-60

60-70

70-80

Total

Class

mark fixi

(xi)

5

15

25

35

45

55

65

75

35

150

25x

455

45y

550

919

675

Σ

Frequency (fr)

7

10

х

13

y

10

14

9

> fi = 63 + x + y

Sum of the frequencies = 100Σifi - 100 =

» 63 + x + y = 100

= x + y = 100 – 63

→ x + y = 37

- y = 37 - x %D

..(1)

Now, the mean of the given data is given

by

- E , fiXi X =

I ,fi

2775 + 25x + 45y

100

42 =

4200 = 2775+ 25x + 45y =

→ 4200 – 2775 = 25x + 45y

→ 1425 = 25x + 45(37 – x)

(1)]

[from1425 = 25x + 1665 – 45x =

→ 20x = 1665 - 1425

→ 20x = 240 =

→ X = 12

If x = 12, then y = 37 – 12 = 25 =

Thus, the value of x is 12 and y is 25.