Extraneous Variables are undesirable variables that influence the relationship between the variables that an experimenter is examining. These variables are undesirable because they add error to an experiment. A major goal in research design is to decrease or control the influence of extraneous Variables as much as possible. (Psychology world, 2017). The extraneous variables can be hold constant by creating a standardized environment and procedure so that all variables are the same in each condition and therefore cannot be confounding. These variables exist in all studies and can interfere with obtaining a clear understanding of the relationship among the study variables. For example, if a study focused on the effect of relaxation therapy on the perception of incisional pain, the researchers would have to control the extraneous variables, such as type of surgical incision and time, amount, and type of pain medication administered after surgery, to prevent their influence on the patient’s perception of pain. Selecting only patients with abdominal incisions who are hospitalized and receiving only one type of pain medication intravenously after surgery would control some of these extraneous variables. Controlling extraneous variables enables researchers to determine the effects of an intervention or treatment on study outcomes more accurately. (Grove, Gray &amp