Question

if the mean of the observation is 12 .
find the value of
0-10
2
10-20
3
20-30
f
30-40
5
40-50
6​

Answer 1

f

i

f

i

x

i

0−10 5 5 25

10−20 15 x 15x

20−30 25 10 250

30−40 35 12 420

40−50 45 7 315

50−60 55 8 440

∑f

i

=42+x ∑f

i

x

i

=1450+15x

Mean=

∑f

i

∑f

i

x

i

⇒ 31.4=

42+x

1450+15x

⇒ 1318.8+31.4x=1450+15x

⇒ 16.4x=131.2

Answer 2

Answer:

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