Recall that study participants were randomly assigned to play the role of gift-giver or gift-receiver. Gift-receivers were asked to provide the level of appreciation (measured on a 7-point scale where 1 = "not at all" and 7 = "to a great extent") they had for the last birthday gift they received from a loved one. Gift-givers were asked to recall the last birthday gift they gave to a loved one and to provide the level of appreciation the loved one had for the gift.
a. Write a dummy variable regression model that will allow the researchers to compare the average level of appreciation for birthday gift-givers (μG) to the average for birthday gift-receivers (μR).
b. Express each of the model's B parameters in terms of μG and μR.
c. The researchers hypothesize that the average level of appreciation is higher for birthday gift-givers than for birthday gift-receivers. Explain how to test this hypothesis using the regression model.
For information: Refer to the Journal of Experimental Social Psychology (Vol. 45, 2009) study of whether buying gifts truly buys love, Exercise 9.9.