A college's job placement office collected data about students' GPAS and the salaries they earned in their first jobs after graduation. The correlation between the two variables was r=0.72. The association appeared to be linear in the scatterplot. The regression equation was: Salary = 2, 830 + 15, 300 GPA %3D a) Interpret the slope in the context of the problem. (4 marks) b) You have just graduated with a GPA of 3.5. What starting salary should you expect? (3 marks) c) What percentage of the variation in starting salaries is explained by the regression on GPA? (3 marks)