Caculate median of the following distribution of data :
`{:("Class Interval",1-10,11-20,21-30,31-40,41-50),("Frequency"," "4," "12," "20," "9," "5):}`

Explanation

Since we are given inclusive series , firstly we convert it into exclusive one by deducting 0.5 from the lower limits and adding 0.5 to the upper limits.

M= size of `((N)/(2))` th item
= Size of `((50)/(2))` th item = Size of 25th item
`:.` Median lies in the class 20.5-30.5.
`M=l_(1)+(N/(2)-c.f.)/(f)xxi`
`=20.5+(50/(2)-16)/(20)xx10` `=20.5+(25-16)/(20)xx10=20.5+(9)/(20)xx10`
`=20.5+4.5=25`
Median =25.