Question

find out mean and median of the following data
Marks. Students
00-10 5
10-20 10
20-30 20
30-40 40
40-50 30
50-60 20
60-70 10
70-80 4​

Answer 1

Answer:

Marks (x) No. of students (f) C.F.

0-10 15 15

10-20 20 35

20-30 25 60

30-40 24 84

40-50 12 96

50-60 31 127

60-70 71 198

70-80 52 250

N = 250

Explanation:

As, N=250⇒

2

N

=

2

250

=125

As 127 is just greater than 125, therefore median class is 50−60.

Median=l+

f

2

N

+C

×h

Here, l=lower limit of median class =50

C=C.F. of the class preceding the median class =96

h= higher limit - lower limit =60−50=10

f= frequency of median class =31

∴median=50+

31

125−96

×10=50+9.35=59.35