Sex ratio is
1 male per 1000 females
1000 females for 1000 males
Number of female for 1000 males
1000 females per 100000 males
Sex ratio is defined as the number of females per 1000 males. It is one of the basic demographic characteristic of a population. Reference : Park&;s textbook of preventive and social medicine, 23rd edition, pg no:482
Demography and family planning