A research question that could be addressed with dummy predictor variables in multiple regression is: Do depression levels (low, medium, and high) predict SAT performance in high school students? The type of coding used is orthogonal to assess for a positive linear pattern, quadratic trend, or an upside- down U. Depression level (D1 = low depression group, D2 = medium depression group, and D3 = high depression group) is the predictor variable which is qualitative and measured on a nominal scale. The outcome variable is SAT performance (Y) which is qualitative and is measured on a ratio scale. The expected outcome is that a relationship exists between depression and SAT performance.

Clarify the uncontrolledcontrast you are trying to calculate.