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.
A brief comment is made about regression equations.