Exam 15: Sampling

Performing a power analysis allows the researcher to calculate the size needed to achieve an adequate sample. Why is it preferable to calculate this number in the design phase of a quantitative study?

A hospital-based nurse researcher at Hospital A conducts experimental research on a rotating bed and its effect on prevention of pressure ulcers in hip fracture patients over 80 years of age with cognitive functional impairment. Because there are so few patients over 80 with fractured hips and cognitive functional impairment, and because the researcher anticipates problems with obtaining consent, a convenience sample is utilized and every patient who meets the criteria and consents is used in the study. The bed, although expensive, is found to be much more effective in preventing pressure ulcers in this population than is turning alone. The study is published. What are the implications of applying these findings, considering the researcher's use of a convenience sample?

A pollster wants to obtain a large sample of voters with the least amount of trouble. Each subject is asked to complete a pencil-paper questionnaire containing seven multiple-choice questions. Each person completing the survey receives a $1 off coupon for a regional coffee chain. The pollster decides to stand outside 20 different supermarkets for 4 hours each and ask patrons to participate in the research. Which method of sampling is this?

The population parameter for firefighters on Long Island is 79% male. The sample statistic for three fire stations is 73% male. Why wasn't the sample statistic the same as the population parameter?

A teacher is supposed to be randomly assigning students to experimental and control groups, for participation in a learning project mandated by the school district. The teacher has an alphabetized master list of the students, numbered 1 through 30. Which is the most logical way to randomly assign the students to group?

A research study examined the partying styles of students in fraternities, in sororities, living in dorms, and living in private residences. Ten students from each group were included in the research. This is an example of which type of sampling strategy?

The researcher conducts a qualitative study that explores the feelings of nurses who care for victims of intentional burning. What sampling methods are most appropriate for this study?