A researcher wants to find out how college students feel about their social security system. Which of the following unbiased methods could the researcher use?

Select all that apply.

Select one or more:

The researcher places a poll question on the main university website and allow students to vote whether or not they like the system.

The researcher sets up a booth outside of the large classroom building and ask students to fill out a survey as they pass.

the researcher randomly selects 10 classes and asks all the students in those classes to fill out an anonymous survey.

The researcher places a survey in the campus paper which students could cut out and mail to the researcher.

the researcher takes a random sample from the enrollment list of the college and surveys the selected students.