Read the question CAREFULLY. For each iteration of the regression model use a new worksheet in excel. Label your answers with the question number and shade in yellow.

The 2008-09 nine-month academic salary for professors in a college in the U.S. The data were collected as part of the ongoing effort of the college's administration to monitor salary differences between male and female faculty members. Answer the following questions based on the provided data. Use a 0.05 significance level where applicable. Use a separate worksheet for each question.

1. Develop an estimated regression equation to predict professors' salaries given the years since their Ph.D.

a. Write down the equation and interpret the estimated regression coefficient for years since Ph.D.

b. What is this model's coefficient of determination (R-square), and what is your interpretation of it?

2. Add gender as an independent variable to the model built in Q1.

a. Is gender a significant variable? What does this outcome mean for this study? Leave this variable in the model regardless of whether it is significant or not.

3. Add discipline (a: theoretical, b: applied) and years of service as independent variables to the estimated regression equation developed in Q2.

a. Based on this model, what is the average difference in salary for a professor in a theoretical vs. an applied discipline, keeping every other variable constant? Which discipline earns more?

b. Develop the best possible estimated regression equation by removing all the insignificant variables. What is the estimated regression equation for this model?