In each of the following situations, evaluate whether the method of sample selection is appropriate for obtaining information about the population of interest. How would you improve the sample design?

(a) ATV talent show with a viewership of 2 million wants to find out whether viewers prefer to have a one-hour final episode or a two-hour final episode. Viewers are invited to call in and vote for their preference. A total of 20000 viewers voluntarily call in and 86%indicate a preference for a two-hour finale. Based on the viewers’ input, the producers arrange to have a two-hour finale.

(b) A voluntary suggestion box at a museum receives 374 entries. In the suggestion box, one out of every four entries is a complaint about the museum’s no-camera policy. The museum’s administrators determine that 75% of museum attendees find the no-camera policy acceptable.

(c) A university student council conducts a student satisfaction survey about catering services. Two representatives from the council survey students as they are entering the cafeteria. After surveying 100 students from a total population of 3000, they find that 76% students are satisfied or very satisfied with cafeteria services.

(d) A graduate student e-mails a survey about dieting to the entire student body (3000). She receives 121 responses.

After compiling her data, she reports that her data represents a “simple random sample of the student body.”

(e) A school district wants to examine the impact of sedentary behavior on academic performance. The total number of students in the district is spread across five schools. The research team lists all of the grade levels, assigning a number to each. Then using a random number table, they select a grade at random and survey every student in that grade about their level of activity and compare this level to their academic performance.