Question

Questions for Exercise 34

Directions: For each of the following excerpts from journal articles, indicate whether the sample is biased or unbiased and explain your choice. In some cases, you may answer "not sure" because there is insufficient information to make a judgment. If you answer "not sure" to an item, describe the additional information you would like to have before making a choice.

1. Researchers state, "A randomized sample of 2,400 surveys was sent to clinical psychology (n = 1,200) and clinical social work (n = 1,200) clinicians from all 50 U.S. states. Of those 2,400 surveys, 711 were returned with usable data, for a response rate of 29.6%."

2. Researchers state, "Participants were 230 first-year university students who responded to signs posted on campus or agreed to participate after being approached individually. Participation was anonymous and participants were paid $10."

3. Researchers state, "Participants in Study 1 had been randomly selected from the membership lists of a large HMO. Because the focus of the research was on marital conflict, families were eligible only if they were intact (parents still living together)."

4. Researchers state, "Participants were 3,446 Internet users... who had been involved in a close relationship. Each participant volunteered to complete an online questionnaire about their dating history at a Web site that features several psychological surveys...."

5. Researchers state, "School guidance personnel selected a representative set of classrooms, taking into account grade level and academic difficulty."

Answer 1