A high school principal wants to gauge student opinion on extending lunch breaks. She places a suggestion box in the cafeteria and encourages students to drop in their anonymous opinions. At the end of the week, 80% of the responses support longer lunch breaks. Which of the following best explains why these results might not represent the opinions of all students in the school?
The principal should have collected more responses.
Only students who feel strongly about lunch breaks are likely to submit responses.
The suggestion box was not placed in every classroom.
The responses were anonymous, so students might not have been serious.
