4,5,6 Please answer these three multiple choice questions

Even if the P-value of the F test in a multiple regression model is nearly zero, it is possible that the R of the model is much less than one. O True False D Question 5 1 pts In selecting independent variables for a regression model, both the forward selection method and the backward elimination method guarantee the optimal combination of the independent variables. True O False D Question 6 2 pts Which of the following would be the most likely result when an irrelevant (or insignificant) independent variable is added to a regression model? A decrease in R2 and an increase in adjusted R2 An increase in both R2 and adjusted R2 A decrease in both R2 and adjusted R2 An increase in R2 and a decrease in adjusted R2