Question
An investigator decides to conduct a study examining the relationship between Facebook usage and anxiety among undergraduate students. She wants to enroll 75 participants from the largest undergraduate dorm on campus. She will measure their “Facebooking” behavior over a 2-week period and then test them for signs of anxiety. Two hundred students respond to her recruitment flyers. 15 are excluded because they do not use Facebook or are not undergrads. She randomly selects 75 students from those who responded and were eligible.
a. Who comprises the study, actual, and target populations?
b. What are two examples of potential external populations to whom the investigator may wish to generalize her results?
c. The investigator realizes after the study is over that the study participants were students who had, on average, come from much wealthier families than the dorm residents as a whole. What sort of validity should she be worried about?
d. The investigator presents results that are very imprecise. What kind of error affects the precision of a study? Is this kind of error best dealt with in the design, or analysis phase of a study?
Source: 250B Problem Bank
