This activity involves some friendly competition.

Divide the class into small groups. Each group is given 15 minutes to come up with as many examples of spurious correlations as they can

(e.g., the correlation between the number of fire trucks at a fire and the amount of fire damage).

Examples given in this chapter or in previous classes are not allowed. After the time is up, a spokesperson from each group presents the group’s spurious correlations to the rest of the class, and the instructor judges whether each one is in fact an example of a spurious correlation. The instructor also keeps a record of all groups’ accepted correlations. The group with the most accepted correlations wins.

Once that has been done, the class examines each correlation individually. The instructor asks for volunteers to name an antecedent third factor that might be causing the two variables to vary together (e.g., it would be the severity of the fire for the fire trucks and damage example given above).