Recall that 955 households were contacted by a female solicitor to raise funds for hazard mitigation research. In addition to the household's level of contribution (in dollars) and the hair color of the solicitor (blond Caucasian, brunette Caucasian, or minority female), the researcher also recorded the beauty rating of the solicitor (measured quantitatively, on a 10-point scale).
a. Write a first-order model (with no interaction) for mean contribution level, E(y), as a function of a solicitor's hair color and her beauty rating.
b. Refer to the model, part a. For each hair color, express the change in contribution level for each 1-point increase in a solicitor's beauty rating in terms of the model parameters.
c. Write an interaction model for mean contribution level, E(y), as a function of a solicitor's hair color and her beauty rating.
d. Refer to the model, part c. For each hair color, express the change in contribution level for each 1-point increase in a solicitor's beauty rating in terms of the model parameters.
e. Refer to the model, part c. Illustrate the interaction with a graph.
For Information: Refer to the Economic Letters (Vol. 100, 2008) study of whether the color of a female solicitor's hair impacts the level of capital raised, Exercise 12.75.