Question

The R2 statistic can decrease when a new regressor variable is added to a multiple linear regression model. A) True B) False

The adjusted R2 statistic can decrease when a new regressor variable is added to a multiple linear regression model. A) True B) False

Cook’s distance is a measure of influence on the regression model for the individual observation in a sample. A) True B) False

Answer 1

1) False because every time predictor is added to a model, the R-squared increases, even if due to chance alone. It never decreases.

2) True because the adjusted R-squared increases only if the new term improves the model more than would be expected by chance. It decreases when a predictor improves the model by less than expected by chance.

3) True because In statistics, Cook's distance is a commonly used estimate of the influence of a data point when performing a least-squares regression analysis.