For the regression equation Q = 100 - 10X1 + 25X2, which of the following statements is true?
- X2 is the more important variable because it is positive
- When X1 decreases by one unit, Q decreases by 10 units.
- When X1 increases by 10 units, Q decreases by 1 unit.
- When X1 increases by one unit, Q decreases by 10 units.