Part of an Excel Output Relating Y (Dependent Variable) and 4

Part of an Excel output relating y (dependent variable) and 4 independent variables, x₁ through x₄, is shown below.
​ $\begin{array}{ll}\hline \text { Regression Statistics } & \\\text { Multiple R } & ? \\\text { R Square } & ? \\\text { Adjusted R Square } & 72.6093 \\\text { Standard Error } & 20 \\\hline\\\\ANOVA\\\hline& d f & S S & M & F&S \\\hline \text { Regression } & ? & 422975.2376 & ? & ?&0 \\\text { Residual } & ? & ? & ? & \\\text { Total } & ? & ? & & \\\\\\\hline & \text { Coefficients } & \text { Standard Error } & t \text { Stat } & \text { P-value } \\\hline \text { Intercept } & -203.6125 & 100.2940 & ? & 0.0605 \\\mathrm{x}_{1} & 0.6483 & 0.1110 & ? & 0.0000 \\\mathrm{x}_{2} & 0.0190 & 0.0065 & ? & 0.0101 \\\mathrm{x}_{3} & 40.4577 & 7.5940 & ? & 0.0001 \\\mathrm{x}_{4}&-0.1.32&20.7823&?&0.9961\\\hline\end{array}$
a.
Fill in all the blanks marked with "?".
b.
At the 5% level of significance, which independent variables are significant and which ones are not? Explain how you arrived at your answers.