Regression demonstration #1

Students find regression difficult to understand because they don't think of measurements as containing random error. To illustrate that measurements do have error, we have some fun by giving them the short, multiple-choice "foreign language test" in Handout 9.1. Then, we give them the "answers" (1=b,2=a,3=c,4=c,5=a,6=b) and have them grade their papers. We ask if anyone got them all wrong. To those people, we explain that the language--"Ugavie" is instinctively understandable by anyone who knows anything about this African tribe. Obviously, the low-scoring students need to be informed about the "Ugavie," so we tell them that the "Ugavie" love them and then present them with the ugliest or most bizarre piece of art we can find and say that it is the Ugavie's most treasured possession. Now that they are informed, we give them a second test (Handout 9.2), score it (answers are 1=a,2=b,3=c,4=c,5=b,6=a), and see if they improved as a result of their familiarity with the Ugavie culture.

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