If a researcher is given a list of all 51,000 students that…
If a researcher is given a list of all 51,000 students that go to the university and the researcher breaks the list up into students who do not work at all, students who work part time, and students who work full time, then selects students from each of these three groups so the sample final sample has 40% non-working students, 40% part time working students, and 20% full time working students to match their population proportions, what type of sampling has occurred?