and R2 for the training and testing data? Compare them with results in Q4.2. iii. What is your final model, after excluding high p-value variables? You will need to use model selection method to obtain this final model. Make it clear what criterion/criteria you have used and justify why they are appropriate. iv. Try Ridge regression with 5-fold CV to select the tuning parameter. Compare its training and testing RMSE and R2 with the previous models