Using 20 observations, the following regression output is obtained from estimating y Intercept X d xd Coefficients 13.12 4.86 Standard Error t Stat p-value 3.20 4.10 0.001 0.54 9.00 0.000 -4.68 5.85 4.41 0.63 -0.80 7.00 0.435 0.000 = 60+61x + 82d + 63xd + E. a. Compute for x= 9 and d= 1; then compute for x = 9 and d= 0. (Round intermediate calculations to at least 4 decimal places and final answers to 2 decimal places.) x=9 and d=1 91.87 x=9 and d = 0 56.86 b-1. Is the dummy variable d significant at the 5% level? Yes, since we reject the relevant null hypothesis. Yes, since we do not reject the relevant null hypothesis. No, since we reject the relevant null hypothesis. O No, since we do not reject the relevant null hypothesis. b-2. Is the interaction variable xd significant at the 5% level? O Yes, since we reject the relevant null hypothesis. Yes, Since we do not reject the relevant null hypothesis. O No, since we reject the relevant null hypothesis. O No, since we do not reject the relevant null hypothesis.