Asocial researcher wants to collect data on study habits of all first-year college students. her daughter, a first-year college student, offers to hand out brief surveys for her mother at her college library where she studies. her daughter mails 20 completed surveys back to her mother. which best describes the 20 completed surveys?
a. a convenience sample that is not representative of all first-year college students
b. a volunteer sample that is a fair representation of all first-year college students
c. a simple random sample biased against male students at the college
d. a simple random sample that is biased against students who were not at the library