Consider the following data for a dependent variable y and two independent variables, x1 and x2. x1 x2 y301294471010825171125116178405945119175747170361211759131427616211 The estimated regression equation for these data is ŷ = −18.37 + 2.01x1 + 4.74x2. Here, SST = 15,182.9, SSR = 14,052.2, sb1 = 0.2471, and sb2 = 0.9484. (a) Test for a significant relationship among x1, x2, and y. Use ???? = 0.05.