I'm having a difficult time understanding the difference between target population and sampled population using stratified sampling. For example, say I want to run some statistics on university students in the UK -- in particular, I want to know specifically about the first-year students. However, let's say the male/female ratio is 70/30, so I want to stratify the samples and take 1000 students from each gender group.
If the target population is defined as the "whole group of interest," does that mean all university students in the UK? If so, then I'm inclined to say the sampled population are university first-years, and the sampling frame is the 2000 students (1000 male/1000 female) chosen from my strata. However, I keep going back and thinking the target population is actually the university first-years in the UK, not the entire university population (first, second, third, fourth years).
Any guidance or tips would be appreciated.