Final answer:
The slopes in the regression equation represent the change in the dependent variable Y with respect to each independent variable; -7 for X1 and +9 for X2. The Y-intercept of 20 represents the expected value of Y when both independent variables are zero.
Step-by-step explanation:
The slopes in the multiple regression equation represent the relationship between the independent variables (X's) and the dependent variable (Y). In the given equation = 20 - 7X₁₁ + 9X₂ₒ, the coefficient of X₁ which is -7, indicates that for every one-unit increase in X₁, the dependent variable Y is expected to decrease by 7 units, assuming all other variables are held constant. Conversely, the coefficient of X₂, which is +9, suggests that for every one-unit increase in X₂, Y is expected to increase by 9 units, all else being equal.
The Y-intercept is the value of Y when all independent variables are 0. In this equation, the Y-intercept is 20. This means that if both X₁ and X₂ were to be zero, the expected value of Y would be 20.