Multiple Regression Help


I need help/advice with multiple regression analysis.

I am looking at the degree of discrimination towards women in construction industry in terms of salary, promotional opportunity, harassment and psychological environment.

Data that I have collected are

-Level of education
-Working hours per week
-Annual salary
-Type of employer
-Working position

The first equation I have to look at salary is

Salary = Age + Gender + Number of years of experience + Education level + working hours per week

Do note that some of the participants did not include their working hours per week but the other data are complete.

Is the above equation correct? Can I use the equation above without working hours per week?

My supervisor gave me a 2nd equation to look at opportunity of promotion,

Equation 2: Promotional opportunity = age + gender + years of exp + edu level + working hours

I don't understand the 2nd equation as how do I tell if there is discrimination towards women in terms of promotional opportunity through the equation above.

And can anyone explain T test, F test and adjusted R2 in plain simple english?