A researcher obtained the average SAT scores of all students in each of the50 states, and the average teacher salaries in each of the 50 states. Shefound a negative correlation between these variables. The researcherconcluded that a lurking variable must be present. By lurking variable shemeansa variable that is not among the variables studied, but that affects theresponse variablethe true cause of a response any variable that produces a large residual the true variable, which is explained by the explanatory variable