試題詳解

29. (5%) According to the following plots of three variables X1, X2, and Y from the data set, please select the correct statement.

(A) X1 is a better linear predictor for predicting Y than X2 since the slope is larger in (a) than in (b)
(B) X2 is a better linear predictor for predicting Y than XI since the correlation is stronger in (b) than in (a)
(C) X1+X2 should be a better predictor than either X1 or X2 since they are positively correlated in (c)
(D) If we build a regression model with X1 and X2 to predict Y, there must be a strong interaction between X1 and X2 since they are positively correlated in (c)
(E) If we fit a multiple regression model with both XI and X2 to predict Y, the coefficients of XI and X2 would both be negative since both X1 and X2 are negatively correlated with Y