This sampling method uses proportionate allocation because we believe there are significant differences between groups comprising the population.

1.  This sampling method uses proportionate allocation because we believe there are significant differences between groups comprising the population. Here we assign the population into groups and then try to replicate those percentages present in the population in our sample.  If the population consists of 20% males and 80% females, then the relative size of the two samples should reflect this proportion in which of the following sampling methods?