Question

Calculate the missing frequency from the following distribution, it being given that the median of the distribution is 24.

Age in years:	0−10	10−20	20−30	30−40	40−50
No. of persons:	5	25	?	18	7

Answer 1

Let the frequency of the class 20−30 be.It is given that median is 35 which lies in the class 20−30. So 20−30 is the median class.

Now, lower limit of median class

Height of the class

Frequency of median class

Cumulative frequency of preceding median class

Total frequency

Formula to be used to calculate median,

Where,

- Lower limit of median class

- Height of the class

- Frequency of median class

- Cumulative frequency of preceding median class

- Total frequency

Put the values in the above,

Hence, the required frequency is 25.