The participants were randomly assigned to play the role of gift giver or gift receiver. This then implies that the treatments gift giver” and "gift received” were imposed on the individuals, thus the study is a designed studty.
(b) The experimental units are the individuals on whom an experiment is performed.
Experimental units=Study participants
A response variable (or dependent variable) is a variable that measures an outcome or result of a study.
Response variable=Level of appreciation of gift
The factors are variables whose levels are manipulated hy the experimenter and thus these variables are controlled by the experimenter.
Factors: Giver or receiver The treatments are what the subjects are subjected to.
Treatments: Giver and Reciever.