What is a relative frequency table and what is it used for?

i will define this concept with the help of simple example (x )----frequency( f)------relative freq(1/f) 1---------------15--------------15/30 2--------------10--------------10/30 3---------------5--------------- 5/30 total ---------30-------------------1

it means each frequency is divided by its overall frequency total. also the sum of relative frequency is always equal to one