You are doing a study to determine the opinions of students at your school regarding stem cell research. Identify the sampling technique you are using when you select the samples listed. Discuss potential sources of bias (if any).

1. You divide the student population with respect to majors and randomly select and question some students in each major.

2. You assign each student a number and generate random numbers. You then question each student whose number is randomly selected.

3. You select students who are in your biology class.