ISYE 6501 Midterm 2. Top Questions and answers, 100% Accurate, rated A+

ISYE 6501 Midterm 2. Top Questions and answers, 100% Accurate, rated A+ Variable Selection - - When two predictors are highly correlated, which of the following statements is true? a) Lasso regression will usually have non-zero coefficients for both predictors. b) Ridge regression will usually have non-zero coefficients for both predictors. - -b) Ridge regression will usually have non-zero coefficients for both predictors. Correct: Ridge regression will choose smaller (in an absolute sense) non-zero coefficients for both models. By nature, it may underestimate the effect of the factors. Which of these is a key difference between stepwise regression and lasso regression? a) Lasso regression requires the data to first be scaled. b) Stepwise regression gives many models to choose from, while lasso gives just one. - -a) Lasso regression requires the data to first be scaled. Correct: If the data is not scaled, the coefficients can have artificially different orders of magnitude, which means they'll have unbalanced effects on the lasso constraint. At each step, the stepwise regression fits a different model. However, different lasso models can be found by varying T, and R has a function to automatically generate multiple lasso models Building simpler models with fewer factors helps avoid which problems? a) Overfitting