For a research project I am working on I am trying to determine if there is a positive relationship between two predictors and a response. My current model is:
Salary = B0 + B1 Cost + B2 SchoolType + B3 Debt + B4 ACTScore + B5 SchoolType * Cost
I know how to test if there is a relationship between multiple predictors and the response using an anova table and F-test. What I want to ascertain here whether there is a positive relationship between cost and salary, taking into account both B1 and the interaction term B5. What kind of model/analysis should I use to do this?