5. A lurking variable is a variable that is not one of the explanatory or response variables but may have an influence on the relationship that you are trying to model.

example 1: A study shows that children who play the piano score higher on intelligence tests.

Lurking variables:

example 2: A study finds that high school students who take the SAT, then enroll in an SAT coaching course before taking the SAT a second time raise their SAT math scores from a mean of 521 to a mean of 561.

Lurking variables: