Sampling Case Studies
Case Study 1 on Sampling
Sampling Hispanic Adults by Telephone1
Problem: Researchers wanted to determine how aware adult Hispanics in the San Francisco area are of product warning messages and signs concerning cigarettes, alcoholic beverages, and other consumer products. The researchers needed to contact a sample of them to interview. A Solution: “Respondents were sampled using…random digit dialing. This procedure…avoids the use of directories with their inherent problem of the exclusion of unlisted numbers while guaranteeing equal probability of selection for all telephone numbers. Such an approach has been used in a number of telephone surveys with Hispanics and has been shown to be not only feasible but also very efficient… “A household was considered to be eligible if those answering the telephone self-identified as Hispanics. Within a given household, the respondent was selected by asking for the Hispanic resident who had most recently celebrated a birthday and who was between 18 and 65 years of age. Interviews were conducted in the language of preference of the respondent (English or Spanish) by bilingual, bicultural interviewers.” Your Opinions:
Note that using random digit dialing gives all telephone numbers, including unlisted numbers, an equal chance of being dialed. Does this procedure give all adult Hispanics in the San Francisco area an equal chance of being selected for the study? Why or why not? 2.
Are there problems with using self-identification as a Hispanic as a criterion for eligibility to participate in the study? Explain your answer. 3.
Speculate on why the interviewer asked to speak with the Hispanic resident between 18 and 65 years of age who had most recently celebrated a birthday. 4.
Would you be interested in knowing whether some Hispanics who answered the phone refused to be interviewed? Why or why not? 1 Source/ reference: Marín, G. (1994). Self-reported awareness of the presence of product warning messages and signs by Hispanics in San Francisco. Public Health Reports, 109, 275-283. Submit your opinion to the case study to this threaded discussion.
Case Study 2 on Sampling
Using a Sample of Convenience1
Problem: Professors often use samples of college students as participants in their research because they are convenient. Using such samples can be problematic. A Solution: A researcher was interested in women’s preferences for married names (traditional – taking the husbands’ surnames and nontraditional – retaining their surnames or hyphenating the two surnames). The researchers surveyed 150 unmarried women students enrolled in an introductory psychology course. They asked the women to indicate what they would do, assuming that their husbands had no opinion on the matter. They were told “If you have not thought much about this issue, please consider it now and give your opinion even if you are not 100% certain.” They were also asked to give the reasons for their name choice. Almost 60% of the women chose to take the husband’s name. In their conclusion, the researchers noted that “one of the most striking results of this study is many respondents’ unquestioning attitudes toward” taking the husband’s surname as indicated by the fact that many gave responses such as “I don’t know, I guess it’s tradition,” or simply writing the work “tradition” as their reason. Your Opinions:
1. Because of the nature of the sample, this study provides information on what women plan to do. Do you think this is as interesting as gathering information on what a sample of married women have done? Why or why now? 2. The researchers apparently suspected that some participants in this sample may not have given the issue much thought before participating in the study and might not be certain of their opinion. In light of this, would it have been interesting to have the students rate the degree of certainty they had in their answers? Why or why not? 3. What is your...
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