Refer to the Following Article

Refer to the following article.
Freshmen Not So Fresh When It Comes To Study Habits
Associated Press - A recent study of all US college students has shown that first-year
students spend less time in the library when compared to non-first-year students. This study was conducted by the Student Life Department on the campus of Essex University in Fowler, New Jersey. The university has a total of 8245 undergraduate students of whom 2316 are first year students. The Student Life Department randomly selected 1600 students consisting of 800 first-year students and 800 non-first-year students and sent out email questionnaires to each. Of the 800 students first-year students, 718 replied to the survey, and of the 800 non-first-year students, 659 replied to the survey. On average, the first-year students reported spending 18.2 hours at the library during a typical week of the academic semester whereas
non-first-year students reported spending 21.5 hours, on average.
What is the population of interest in this study?