Question

2. Find the median for the following dada
marks 0-10 10-20 20-30 30-40 40-50
no of students 3 4 2 7 10​

Answer 1

Here, the class intervals are of unequal width. If the class intervals are of unequal width the frequencies need not be adjusted to make the class intervals equal.  

Calculation of Median

Marks No. of students (frequency) Cumulative frequency

0-10 5 5

10-30 15 20

30-60 30 50

60-80 8 58

80-90 2 60

N=∑f  

i

​  

=60

Here, N=60∴N/2=30

The cumulative frequency just greater than N/2=30 is 50 and the corresponding class is 30−60 . Hence, 30−60 is the median class.

∴l=30,f=30,F=20,h=30

Now, Median =l+  

f

2

N

​  

−F

​  

×h

⇒Median=30+  

30

30−20

​  

×30=40