Question

1. Using data on a sample of less-developed nations, a regression of Y = mortality rate (deaths per 1000 population), X₁ = percentage of population who have completed high school, and X₂ = gross domestic product (GDP) yields the following equation: EY=34.53-0.13X1-0.64X2.
   1. Interpret the OLS coefficient for X₁.
   2. Suppose you are asked to sketch on a single graph the predicted relationships between Y and X₁ when X₂ = 0, X₂ = 10, and X₂ = 20, are you going to get the same slope for different lines? How about the intercepts?
   3. The bivariate regression equation of Y on X₁ is EY=37.65-0.31X1. Explain why the bivariate and multiple regression coefficients on X₁ are quite different.

Answer 1