Lesson Introduction

Hi there! Today, we're going to learn how to apply Linear Regression to a real dataset. Working with real data shows us how machine learning solves real problems. We'll use the California Housing Dataset. By the end of this lesson, you'll know how to use Linear Regression on a real dataset and understand the results.

Understanding the California Housing Dataset

Before diving into the code, let's understand the dataset we'll be working with. The California Housing Dataset is based on data from the 1990 California census. It contains information about various factors affecting housing prices in different districts of California.

Here's a quick overview of the columns in the dataset:

  • MedInc: Median income in block group
  • HouseAge: Median house age in block group
  • AveRooms: Average number of rooms per household
  • AveBedrms: Average number of bedrooms per household
  • Population: Block group population
  • AveOccup: Average household size
  • Latitude: Block group latitude
  • Longitude: Block group longitude
  • MedHouseVal: Median house value for California districts (This is our target variable)
Loading and Preparing the Data: Part 1

First, let's load our data. Think of this step as getting all the ingredients ready before cooking. Here's the code to load the dataset:

We used the fetch_california_housing function to load the dataset and convert it to a Pandas DataFrame for easier handling.

Loading and Preparing the Data: Part 2

Now, let's select our features and target. In the California Housing Dataset, we'll use all features except for the target column (MedHouseVal).

Here's the code:

We drop rows with missing values and select all features except the target.

Initializing and Training the Model

Next, we create and train our Linear Regression model. Think of it as teaching a kid to ride a bike: you show them a few times, and then they get the hang of it.

Here's the code:

The LinearRegression() function initializes the model, and model.fit(X, y) trains it using our data.

Making Predictions

Once our model is trained, it's ready to make predictions. This is like the kid finally riding the bike on their own.

Here's how you can make predictions:

The model.predict(X) function uses the model to predict house prices based on the feature values.

Understanding the Model Outputs

It's important to understand how the model is making predictions. In a Linear Regression model, we have an intercept and coefficients for each feature. Think of the intercept as a starting point and the coefficients as slopes.

Here's the code to display them:

The model.intercept_ gives us the intercept, and model.coef_ gives us the coefficients for each feature.

Evaluating the Performance

Finally, we'll calculate the Mean Squared Error (MSE) to evaluate how well our model is doing. Think of it as checking if the kid can ride the bike without falling.

Here's the code to calculate MSE and make conclusions:

The mean_squared_error function computes the MSE, which tells us how close our predictions are to the actual values. A lower MSE indicates a better fit.

Lesson Summary

Great job! Today, we learned how to apply Linear Regression to a real dataset. We loaded the California Housing Dataset, selected features and target, trained a model, made predictions, and evaluated the results. Understanding how to work with real datasets is a key skill in machine learning.

Now it's your turn! Move on to the practice exercises where you'll apply what you've learned to another real dataset. You'll load data, train a model, make predictions, and visualize the results. Happy coding!

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