An economic forecasting model has ban developed for predicting next year's total national retail sales, Of the dozens of economic variables that are known to have wn effect on the retail sales, 14 of them (r Cy, so) are selected for use in a multiple regresdon model. Using 189 years" worth of observations on cach of the variables and the retail sales, a multiple regrevdon model is fit to the data. For this model, what are the degrees of freedom (of) for the regression wm of squares, oror sum of squares, and total sum of squareat (a) of for the regression sum of squares! (b) of for the error sum of squares: (c) df for the total sum of squares: E