A very good question you might be asking at this point is how to
evaluate your linear regression.
One of the obvious things that you can do is visualize the regression on top of
your scatter points.
Another thing you can do is you can look at the errors that your
linear regression makes.
By errors, I don't mean mistakes, not exactly.
What I mean by errors is something like this.
Suppose I have my age and net worth data.
And it will be following along in some pattern, although not perfectly linear.
I fit my line to it.
And this fit is going to have associated errors.
In this context, errors is a technical term and that's the difference in
this example between the actual net worth of a particular person and
the net worth that's predicted by our regression line.