In a research study, which factor would be considered a lurking variable that could influence the results?

• A. The independent variable manipulated by the researcher.
• B. The dependent variable being measured.
• C. An uncontrolled external factor that affects both the independent and dependent variables.
• D. The sample size used in the study.

Answer: (C)

A lurking variable is an external variable that has not been accounted for in the study but can influence both the independent and dependent variables, potentially confounding the results. In research, it is crucial to identify and control for these lurking variables to ensure that any observed effects can be attributed only to the manipulated independent variable, and not to these extraneous factors.

In this context, the uncontrolled external factor that affects both the independent and dependent variables fits the definition of a lurking variable. For example, if a study is examining the effect of a new educational program (independent variable) on student test scores (dependent variable), a lurking variable could be the socioeconomic status of the students, as it could impact both their access to educational resources and their overall academic performance.

The independent variable manipulated by the researcher plays a direct role in the study's design, and the dependent variable is what is being measured as an outcome; therefore, they are not considered lurking variables. The sample size is important for the statistical validity of the results but does not serve as a lurking variable that would influence the relationship between the independent and dependent variables. Thus, the identification of an uncontrolled external factor that impacts both directly corresponds to the essence of a lurking variable.