Using the sat dataset, the data set is in R in the faraway package. fit a model with the total SAT score as the response and expend, salary, ratio, and takers as predictors. Perform regression diagnostic on this model to answer the following questions. Display any plots that are relevant. Do not provide any plots about which you have nothing to say.(a) Check the constant variance assumption for the erros; •(b) Check the normality assumption; •(c) Check for large leverage points; •(d) Check for outliers; •(e) Check for influential points.