You are given a marketing data set (marketing.csv). The dataset contains the impact of three advertising medias (youtube (x1), facebook (x2) and newspaper (x3)) on sales (y). Data given are the advertising budget in thousands of ringgit Malaysia (RM) along with the sales. Answer the following questions and provide the output as well as R scripts for the answer. a. Provide scatter plot for each model (y vs x1, y vs x2, y vs x3). What can you conclude from these scatter plots? b. Use the least squares formulas to fit three straight-line models-one for each independent variable- for predicting y. c. Interpret the estimated slope coefficient b in each model and test the utility of each model by testing HO: = 0 against HI: B # 0. d. Find the coefficient correlation r and coefficient of determination r2, for each model. Explain and interpret the values of r and r2 for each relationship. Indicate which independent variables predicts y best for the data. e. Conclusion - conclude and summarize your findings (you can give support/justification and do citation whenever necessary from your readings why the selected independent variable is the best to predict y)