Hi.. I am working on female and male tertiary enrolment rates and its impact on meritocracy. For the analysis I ran four different regressions 1) with overall tertiary enrolment rate 2) pure female tertiary enrolment rate 3) pure male tertiary enrolment rate 4) tertiary enrolment ratio. I have generated the ratio variable simply by dividing female enrolment with male enrolment rate. Is this the correct way as numerator or denominator may contain 0 value as well.