11.76 Models with interactions.

Suppose that is an indicator variable with the value 0 for Group A and 1 for Group B, and is a quantitative variable. Each of the following models describes a relationship between and the explanatory variables and . For each model, substitute the value 0 for , and write the resulting equation for in terms of for Group A. Then substitute to obtain the equation for Group B, and sketch the two equations on the same graph. Describe in words the difference in the relationship for the two groups.