Problem 4 (10 points) The following two linear regression models were fit to 20 observations: . Model 1: y = Bo + B1x1 + Bx2 + Model 2: y = Bo + Bx1 + Bx2 + 3x3 + B4x4 + The results of the regression are as follows: Model Number Residual Sum of Squares Regression Sum of Squares 13.47 22.75 25.70 10.53 1 2 The null hypothesis is Ho: 33 = both equal to zero. Calculate the statistic used to test Ho. B4 = 0 with the alternative hypothesis being that the two betas are not