GROUP TASK #9: Issues in Sampling
For each study, identify one or more issues that may potentially cause the sample to be biased.
An orchestra manager is eager to better understand the likes and dislikes of the orchestra’s audience. She distibutes a survey to the first 50 people who arrive at the orchestra’s gala December matinee concert.
A researcher is interested in which local radio stations are most listened to by people when driving. The researcher makes a deal with ten local garages. Whenever a car is brought into the shop, the mechanic first turns on the car radio and records the station to which the radio is tuned. After a month of collecting data, the researcher has over two thousand observations.
A researcher is interested in voice-leading practices. He encodes the complete fugues from the Bach Well-Tempered Clavier and writes software to test various hypotheses in the musical organization.
A researcher wants to sample opinions from people attending a nightclub. The quietest places in the club to conduct verbal interviews are the restrooms. Two male and two female research assistants are stationed inside the restrooms where they approach everyone who is about to leave the restroom to answer a couple of quick questions.
Felix Mendelssohn wrote thousands of letters over the course of his life. A historical musicologist conjectures that Mendelssohn became increasingly religious towards the end of his life. From a complete list of letters, the researcher randomly selects 200. Each letter is read by the researcher and coded (yes/no) for whether it contains any spiritual, biblical or religious allusion or content.
A researcher is interested in learning how much musicians earn and their various sources of income. The researcher succeeds in getting the e-mail list for all of the members of the American Federation of Musicians who have provided the AFM with an e-mail contact. An e-mail is sent to members soliciting participation. The e-mail contains a link to the survey’s website.
In the early 1980s, Christa Hansen was eager to test whether non-Westerners also show evidence of statistical learning for pitch relationships. Her aim was to recruit listeners who were not familiar with Western musical culture. Along with her husband, Putra, Hansen set out on a small motorcycle toward the remote northeastern region of the island of Bali. Whenever they met someone they asked two questions: “What is the most isolated village in this area? And does it have a gamelan?” Having reached this village, they again asked the same questions, and so continued on their quest. When they were no longer able to use their motorcycle, a footpath took them to a remote village in the shadow of the Gunung Agung volcano. Hansen concluded that she had reached a truly isolated place when the villagers surmised that this fair-skinned stranger must be Javanese. Recruiting twenty-seven participants from this village, Hansen was able to collect data for her experiment.
Sandra Trehub and her colleagues regularly carry out musical studies with newborn infants. From local-area hospitals, they are able to get contact information with names and telephone numbers of mothers who have recently given birth in the various hospitals. They recruit participants by phoning the mothers, describing the basic aims of their experiments, and asking whether they would be willing to participate in an experiment with their new infant. A small sum (roughly $20) is paid to volunteers. Since the research lab is located in a suburban area, there is ample parking. There is also reasonable bus service.