Two ad agencies want to understand issues that are important to students. Agency A will interview 50 students whose names are randomly chosen from school enrollment data. Agency B will interview 50 randomly selected people from those who respond to a social media posting. Which method will produce a fair sample of the student population and why?
Agency A actually gets people who are in school, but Agency B might get people who don't go to school, while you want issues that are important to students, not anyone else.
