Question

Calculate the median from the following data - set :
`{:("Size",10-15,15-17.5,17.5-20,20-30,30-35,35-40,40-50),("Frequency"," "10," "15," "17," "25," "28," "30," "40):}`

Answer 1

Even thought the class intervals are unequal , no specific treatment of the data is needed. Median can be calculated straight away as in the case of other frequency distributions.

M = Size of `((N)/(2))` th item
= Size of `((165)/(2))` th item
= Size of 82.5 th item
Hence , median lies in the class 30-35.
`M=l_(1)+(N/(2)-c.f.)/(f)xxi`
`=30+(165/(2)-67)/(28)xx5=30+(15-5)/(28)xx5`
`=30+2.77=32.77`
Median = 32.77.