Question

Find the mean marks of the students from the following frequency distribution using assumed-mean method: 0−10 10 10−20 12 20−30 9 30−40 15 40−50 6 50−60 10 60−70 7 70−80 16 80−90 10 90−100 5

Answer 1

Step-by-step explanation:

ANSWER

Class

interval

Mid Values

x

i

Frequency

f

i

d

i

=X

i

-A

u

i

=

h

x

i

−A

f

i

u

i

0-10 5 10

-20 -2 -20

10-20 15 9 -10 -1 -9

20-30 25 25 0 0 0

30-40 35 30 10 1 30

40-50 45 16 20 2 32

50-60

55 10 30 3 30

Let A=25 and h=10

X

=A+

∑f

i

h×∑f

i

u

i

=25+

100

10×63

=25+6.3=31.3.

Hence, the mean is 31.3.

Answer 2

Step-by-step explanation:

x=£xi.fi/£f

this is formula for

mean