Please help me with solving questions (a), (b) and (c) Provide the steps to get to the final solution. THANKS a lot!

A large university leeeps track of its students when they enter the labor market after leaving school. Specically, they collect data on their students' starting salaries (in thousands of US. dollars), gender, and whether the student graduated from a STEM (science, technology, engineering, maths) eld. These variables are denoted inc, male, and stem, respectively. The following model is then estimated using 0L3 ima- = 60 + Blmaiez- + ul- (1) (a) Take the expectation of equation (1) conditional on male = 1 and male = I} (one at a time). What is ,31 equal to? How do you interpret 61? To account for the fact that there is a higher demand for STEM graduates, and that the graduates from these elds tend to end up at jobs with higher salaries, a researcher wanted to change the model specication. To nd out whether graduating from a STEM eld is more benecial for men than for women, the following model was estimated using 0L3 inc,- = 60 + lmale, + 623mm,- + gmale, >