Yes, because her class represents a random sample of students in the school. Instead of asking every single student in the school, which would take too long, it is much easier to poll a small group of people to see what they think, and then have their opinion represent a larger community. Although if Maggie had asked more people, her answer would have been more precise, the sample could still be highly accurate. Hope this helps even though I am asking the day after this was posted and this question is in the wrong subject. It should be in math, but it's not that big of a deal.
