A university's housing and residence office wants to know how much students pay per month for rent in off‑campus housing. The university does not have enough on‑campus housing for students, and this information will be used in a brochure about student housing. They obtain a list of the 12 , 304 students who live in off‑campus housing and have not yet graduated and mail a questionnaire to 200 students selected at random. Only 78 questionnaires are returned. (a) What is the population in this study? Be careful: about what group do they want information?