Question: The survey in Exercise has been conducted annually by the Higher Education Research Institute at UCLA since 1966. One of the results reported was that "students' disengagement from politics continues. The percentage of freshmen believing that ‘keeping up to date with political affairs' is important fell to 26.7 percent, down from 29.4 percent a year ago [in 1996] and a high of 57.8 percent in 1966." In 1966, college students were in the midst of protesting the Vietnam War, and in 1996 there was a presidential election. Do you think the results of this survey indicate that first-year college students have become more apathetic in general? Explain.
Exercise: An article in the Sacramento Bee (12 January 1998, p. A4) was titled "College freshmen show conservative side" and reported the results of a fall 1997 survey "based on responses from a representative sample of 252,082 full-time freshmen at 464 two- and four-year colleges and universities nationwide." The article did not explain how the schools or students were selected.
a. For this survey, explain what a unit is, what the population is, and what the sample is.
b. Assuming a random sample of students was selected at each of the 464 schools, what type of sample was used in this survey? Explain.
c. Now assume that the 464 schools were randomly selected from all eligible colleges and universities and that all first-year students at those schools were surveyed. Explain what type of sample was used in the survey.
d. Why would one of the two sampling methods described in parts b and c have been simpler to implement than a simple random sample of all first-year college students in the United States?