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Okay, so that was rewriting the model for just a single observation.
But it's gonna be very, very helpful in our deriving these algorithms
to write the equation for all the observations stacked up together.
Okay so, we're gonna have to dig through a little bit of linear algebra
in order to have a really nice closed form solution for fitting this model.
So let's start by just stacking up all our observations,
taking all these pink squares that I showed on this previous slide here and
putting them into one big vector.
Where this vector is my first house sale, my second house sale,
my third house sale, all the way up to how many observations do I have in my dataset?
Capital N, that's my capital Nth house sale and I can write
the model for all these observations in this big matrix vector notation,
where here again I have this W vector that we talked about before.