QUESTION 9 Consider the multiple regression model with two regressors X1 and X2, where both variables are determinants of the dependent variable. When omitting X2 from the regression, then there will be omitted variable bias for: O a. if X1 and X2 are correlated. O b. always. O C. if X2 is measured in percentages. O d. if X2 is a dummy variable. O e. All of the above. O f. None of the above.QUESTION 10 The main advantage of using multiple regression analysis over differences in means testing is that the regression technique: O a. allows you to calculate p-values for the significance of your results. O b. provides you with a measure of goodness of fit. O c. gives you quantitative estimates of a unit change in X. O d assumes that the error terms are generated from a normal distribution. O e. All of the above. Of. None of the above.QUESTION 11 In the multiple linear regression model, omitted variable bias: 0 a. will always be present as long as the regression R2