1.
We intentionally ignored some of the output of these regression models, for the sake of simplicity. It would be quite valuable for you to understand those missing parts, however. In particular, we ignored the "p-values" associated with the t-tests on the slope/Bweight estimates and we also ignored the overall F-statistic reported at the very bottom of the output. There are tons of great recourses on the web for explaining what these are.
For a super bonus, you could also investigate the meaning of the "Adjusted" r-squared that appears in the output.
