A multiple regression was performed on a sample of 16 observations. The estimated equation is #=23.5 - 14.28x1 + 6.72x2 + 15.68x3. The standard errors for the coefficients are $1 = 4.2, $ 2 = 5.6, and $:3 =2.8. For this model, SST = 3809.6 and SSR = 3285.4. a. Test for the significance of B1: 82, and By at the 5% level of significance. Do you think any of the variables should be dropped from the model? Compute the R- squared (the coefficient of determination) R and the adjusted R-squared Ra. Interpret R. b. Use the Ftest to test the significance of the relationship among the dependent variable and the (non-constant) regressors at the 5% level of significance