Question

find the median of the following data. C.I. 5-10 10-15 15-20 20-25 25-30 30-35 35-40 Frequency 4 45 20 13 9. 7 2.​

Answer 1

Answer:

Class Frequency (f

i

) c.f.

5−10 5 5

10−15 6 5+6=11

15−20 15 11+15=26

20−25 10 26+10=36

25−30 5 36+5=41

30−35 4 41+4=45

35−40 2 45+2=47

40−45 2 47+2=49

∑f

i

=49

Where c.f.= cumulative frequency

Median =L+

h×

f

(

2

N

−c.f.)

⎭

⎪

⎪

⎪

⎬

⎪

⎪

⎪

⎫

Here

N=49

2

N

=24.5

c.f. just greater than 24.5 is 26

Median class =15−20

So, L=15, h=5, f=15 and

c.f.=c.f. of preceding class i.e 11

Substitute all the value in the above formula, we get

Median =15+(

15

24.5−11

)×5

Median =15+4.5=19.5

Thus, median of frequency distribution is 19.5.