Lesson: Challenging Critical/Logical Reasoning - 12t01

Reasoning Classics: The Representativeness Argument, continued

Let's look at a typical representativeness argument.

Our school principal wanted to determine whether there was enough demand for the school cafeteria to provide vegetarian entrees during lunch. He surveyed student council members and found that 90 percent of them said they would choose a vegetarian entrée if one were offered. Because of this overwhelming support, the principal decided to start offering vegetarian entrees.

Was the principal justified in his decision? What must he have assumed? Click Continue to see our answer.

The principal based his decision on a survey of student council members. Are they representative of the students at the school in general? Probably not. The principal, however, assumes that the student council members surveyed are, in fact, representative of the school's student body. If vegetarian entrees will be popular with student council members, they will be popular with the student body.

And this will always be the underlying assumption in a representativeness argument: that the sample used as evidence is representative of the larger group.

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