The Standard Error of the Estimate for a Multiple Regression

Multiple Choice

The standard error of the estimate for a multiple regression model with two explanatory variables X₁ and X₂:

A) measures the variation around the predicted regression equation.
B) measures the proportion of variation in Y that is explained by X₁ and X_2.
C) measures the proportion of variation in Y that is explained by X₁ holding X₂ constant.
D) has the same sign as b₁.