Question

The median of the following data is 16. Find the missing frequencies a
and bif the total of frequencies is 70.
Class
0-5
5-10
10-15 | 15-20 | 20–25 25–30 30–35 35-40
12
12
b
15
6
Frequency
6
a
4
Ft to
[CBSE 2013]​

Answer 1

Answer:

Class Interval         Frequency     cf0−512125−10a12+a10−151224+a15−201539+a20−25b39+a+b25−30645+a+b30−35651+a+b35−40455+a+b=70Here:

N=70

N/2=35

Median =16, Median class =15−20

So, I=15, h=5, f=15 and

xf=xf of preceding class i.e.24+a

We know,

Median =1+⎩⎪⎪⎪⎨⎪⎪⎪⎧h×f(2N−cf)⎭⎪⎪⎪⎬⎪⎪⎪⎫

Substitute all the value in the above formula, we get

16=15+{5×(3