Answer:
1) the students in the hallway
2) the group of students
3)the students in two classrooms
4) she should ask a random group of students in the hall
Explanation:
1) because it's a random group of people, but if they asked people getting off the bus obviously all of them get the bus sothe results wouldn't be accurate
2) since he wants to know what's best for students, he has to ask students the questions
3) because then you will get a mixture of people with different tastes, and a better representative of all the students
4) if she selects a random group, you're more likely to have people with different views and opinions, making your research more accurate