1. Calculate the residual sum of squares (SSE) by subtracting the sums of squares for radio and newspaper advertising from the total sum of squares: (2028032.69 - 1216940 - 632259.4483 = 179833.2417).
2. Calculate the mean square error (MSE) by dividing SSE by the degrees of freedom for the residuals: (179833.2417 / 19 ≈ 9464.907).
3. Calculate the F-statistic for newspaper advertising by dividing its sum of squares by the MSE: (632259.4483 / 9464.907 ≈ 66.82). The closest answer is 45.33, so the correct answer is c. 45.33.