Paul surveyed students in a high school about their favorite sport of the 1, 200 students in the school, 67 tenth-grade students were surveyed. More than half of the 67 students said their favorite sport is basketball. Based on the survey, Paul concluded that the favorite sport of most high school students is basketball. Why is Paul's conclusion incorrect?

1 Paul surveyed too many students.
2 Paul's survey sample only included tenth graders.
3 Paul did not survey any middle school students.
4 Paul did not include enough sports in the survey.