You want to know which graduate class (first-years to seniors) is more satisfied with its degree program (on a scale of 1=Unsatisfied to 5=Satisfied); so, you survey students to compare differences:
1- What is the dependent variable, Y?
2- What is the level of measurement for the dependent variable, Y?
3- What is the independent variable, X?
4- What is the level of measurement for the independent variable, X?