R_eqnirem-ts You are required to submit an Excel file containing the tables and plots needed to assess both regression models - i.e., your simple regression and multiple regression models including the Excel output tables for the regression, as well as the residual plots, line t plots and normal probability plots for use in specication tests. You should also include the correlation matrix for your dependent and independent variables. Submit a Word le to serve as a cover page for your regression models with the following: 1) Provide your best estimated cost function for Salaries 3: related costs. 2) Interpret this cost function, including the statistical validity and significance of your regression results. 3) Apply the six specification tests. Do any of them suggest that one [or more] of the regression assumptions have been violated? 4)