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Course: High school statistics?>?Unit 5
Lesson 2: Potential problems with samplingBias in samples and surveys
Problem
A high school has a policy that students' phones must be kept away during class. A principal used the school roster to poll a random sample of students, and only said that they ever had their phone out during class. The next day, the principal observed classrooms and noticed that approximately of students had their phone out at some point during class.
Which of these is the most concerning potential source of bias in the principal's poll?