Problem 2 [15 pts] For the sat data, t a model with the total SAT score as the response and expend, salary, ratio and takers as predictors (same as the last homework). Perform regression diagnostics on this model to answer the following questions. Display any plots that are relevant as you go. Note: do not provide any plots about Which you have nothing to say. Suggest possible improvements or corrections to the model Where appropriate. (a) State the tted linear model. (b) Check for large leverage points and display graphically on a half- normal plot. (c) Check for outliers using jackknife residuals, and use the Bonferroni correction to decide if the largest outlier is signicant at the 5% level. (d) Check for inuential points using Cook's D statistic and display graph- ically on a half-normal plot. Comment on whether anything is notable. (e) Calculate the VIF for each predictor. Comment on Whether anything is notable