Which kind of sampling plan was used in each of the following situations? Would the plan result in an unbiased sample? (Select all that apply.)

(a)

Complaints have been made about students not showering after physical education class at a high school. The administration is trying to decide whether to begin requiring showering. They divide the set of interested people into three groups: teachers, students, and parents. A random sample is selected from each group and asked to fill out a brief questionnaire about the need to shower after P.E. class.

voluntary sample

convenience sample

simple random sample

stratified random sample

systematic sampling

cluster sample

(b) The managers of a large shopping mall are trying to decide whether to add another information booth to the concourse. They hire a student to stand by one door and ask the next 100 people who enter the mall whether they would like to see another information booth added to the mall and, if so, where.

voluntary sample

convenience sample

simple random sample

stratified random sample

systematic sampling

cluster sample

(c)The managers of the new cafeteria on campus want to measure student satisfaction with the new facilities and food offerings. They decide to pass out questionnaires to students who go through the line between the times 8:15 and 8:30, 11:15 and 11:30, 2:15 and 2:30, and 5:15 and 5:30 and ask them to complete the questionnaires. They leave a box at the exit door for completed questionnaires.

voluntary sample

convenience sample

simple random sample

stratified random sample

systematic sampling

cluster sample

(d)Three users of the Panther, a new car, reported problems with the trunk lid popping up while driving. The car manufacturer test drove the next 30 cars leaving the factory and found that the trunk lid did not pop open. The manufacturer decided that the problem did not need to be addressed any further.

voluntary sample

convenience sample

simple random sample

stratified random sample

systematic sampling

cluster sample

(e)A bookstore is contemplating putting in a coffee bar to attract customers. For three days (December 21-23), they ask each customer who buys a book whether he or she would like to see a coffee bar added to the store.

voluntary sample

convenience sample

simple random sample

stratified random sample

systematic sampling

cluster sample