## Linear regression with multiple features

Single feature linear regression is really simple. All you need is to find function that fits training data best. It is also easy to plot data and learned curve. But in reality regression analysis is based on multiple features. So in most cases we cannot imagine the multidimensional space where data could be plotted. We need to rely on methods we use. You have to feel comfortable with linear algebra where matrices and vectors are used. If previously we had one feature (temperature) now we need to introduce more of them. So we need to expand hypothesis to accept more features. From now and later on instead of output y we are gonna use h(x) notation: As you can see with more variables (features) we also end up with more parameters θ that has to be learned. Before we move lets find suitable data that we could use for building …