[MUSIC] Okay, so far we've assumed that the only
feature relevant to the value of my house, is the square feet of the house. But I dig into the data
set a little bit more, and I look at a house that's supposed
to be very similar to mine. It's a house that has very
similar square footage. And so, this house is definitely making an
influence on what the predictions are for my house. But I look at it and I say, and
I look at the specific listing, and it shows that that house
only had one bathroom. It's actually quite a big house,
only one bathroom. And I say that's really,
really not comparable to my house, which has three bathrooms. So that the value of that house,
that house sales price really shouldn't be indicative of
what my house sales price should be. So instead what we can think about
doing is adding more features. So instead of just looking at
the relationship between square feet and price, we can add number of bathrooms. And now for each one of the listings that I looked at
before, I'm gonna have to go through and record how many square feet that house
had, and the number of bathrooms. And I'm gonna plot each of
these points in the 3D space. Okay?
So it's this hyper cube of square feet versus bathrooms versus price. And now instead of fitting a line to the
data, if I'm thinking about just a very simple model,
I can think about fitting a hyper plane. Okay, so
it's just a slice through the space. We're here. This is the equation of the hyper plane,
and this is the equation of this plane. So we have w0, which is our intercept,
just where this plane lives up and down on the y-axis. And we have w1 times
the number of square feet, and w2 times the number of bathrooms. But a question is where do we stop? Do we just want to include the number
of bathrooms as our additional feature? There are lots of things we
could think about including. We could think about in addition to
our square feet, number of bathrooms, there's the number of bedrooms,
the lot size, how old the house is, and the list goes on and on. In terms of different properties of
the house that could be influential in assessing it's value. But we're gonna actually hold off on this
question of looking at which features are important for this regression task,
until we get to the regression course. So go to the regression course
to learn more about this topic. [MUSIC]