Question

If the mean of the following data is 35, find out the missing frequency f?
0-10
20-30
Class
Frequency
10-20
3
30-40 40-50 50-60
6 5 5
7
2​

Answer 1

Answer:

ANSWER

Class interval frequency cumulitative frequency

0−10 2 2

10−20 3 5

20−30

x 5+x

30−40 6 11+x

40−50 5 16+x

50−60 3 19+x

60−70 2 21+x

Total frequency= 21+x

=> N=21+x

=>

2

N

=

2

21+x

So; CF corresponding to this is 11+x

And class corresponds to this is 30−40

So, l=30 , F=5+x , f=6 and h=10

Median=l+

⎝

⎜

⎜

⎛

f

2

N

−F

⎠

⎟

⎟

⎞

×h

=> 35=30+

⎝

⎜

⎜

⎛

6

2

21+x

−5−x

⎠

⎟

⎟

⎞

×10

=> x=5