17. Polling College Students In conducting polls of college students, it is increasingly difficult to get a random sample of college students in which every college student has the same chance of being included in the sample. Consider the following scenario used by the Gallup organization24 to select a random sample of students at 4-year colleges.

“It selected a random sample of 240 U.S. four-year colleges, drawn from the Integrated Postsecondary Education Data System (IPEDS). Then Gallup contacted each of those 240 schools in an attempt to obtain a sample of their students; just 32 colleges agreed to participate, with Christian schools overrepresented

. . . .” An email invitation was sent to a portion of those students followed by a phone call.

The response rate was 6%.

Discuss how problems of nonresponse and undercoverage might bias the results of a survey conducted under these conditions.