Regression with Linear Models
Regression
is a type of supervised learning used to predict continuous numerical values.
Unlike classification, where we predict categories, regression estimates a numeric output based on input features.
The following are some example uses of regression:
- Predicting house prices based on square footage
- Estimating temperature from weather data
- Forecasting sales from historical trends
Types of Linear Regression
Simple Linear Regression
: Uses one feature to predict a target.Multiple Linear Regression
: Uses multiple features to predict a target.Regularized Linear Regression
: Adds a penalty to reduce overfitting (e.g., Ridge, Lasso).
Example: Predicting House Prices
The following example shows how to use linear regression to predict house prices.
Linear Regression Example
from sklearn.linear_model import LinearRegression
from sklearn.model_selection import train_test_split
from sklearn.metrics import mean_squared_error, r2_score
import numpy as np
# Sample dataset
X = np.array([[1000], [1500], [2000], [2500], [3000]]) # square footage
y = np.array([200000, 250000, 300000, 350000, 400000]) # prices
# Train/test split
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)
# Create and train model
model = LinearRegression()
model.fit(X_train, y_train)
# Predictions
y_pred = model.predict(X_test)
# Evaluation
mse = mean_squared_error(y_test, y_pred)
r2 = r2_score(y_test, y_pred)
print("Mean Squared Error:", mse)
print("R² Score:", r2)
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