Drake had hypothesized that more freshmen than seniors engage in "head scratching." In order to test this hypothesis, he has to provide a specific description of the behavior that he would count as "one head scratching." Would scratching the ear or the forehead be included? What if the student "scratched his head" against a book or door? Would these also be counted in the study? This specific description of the behavior to be counted is called:.a. the hypothesis. b. the theory. c. procedure. d. operational definition.

(D) Operational definition

Explanation:

  The operational definition is one of the type of fundamental method that is specifically used to determine the various types of properties by collecting the specific information or data that helps in making various types of decisions.

According to the given question, the description about the specific behavior is basically counted on the basis of the operational definition as it helps in measuring the various types of theoretical based constructs.

  Therefore, Option (D) is correct answer.    

answer; i believe the correct answer is (117);

i would say b. research typically uses a variety of sources