Linear Regression
How it works geometrically:
Finds the best-fitting straight line through data points by minimizing the sum of squared distances (residuals) from points to the line. The line represents the relationship y = mx + b.
Logistic Regression
How it works geometrically:
Uses a sigmoid (S-shaped) curve to separate classes. The curve maps any input to a value between 0 and 1, representing probability. Decision boundary is typically at 0.5 probability.
Decision Tree
How it works geometrically:
Creates rectangular decision regions by making binary splits parallel to feature axes. Each split divides the space into two regions, creating a tree-like hierarchy of decisions.
Random Forest
How it works geometrically:
Combines multiple decision trees, each creating different rectangular regions. The final decision is made by majority voting, creating smoother, more robust decision boundaries.
Support Vector Machine
How it works geometrically:
Finds the optimal hyperplane that maximizes the margin between classes. Support vectors are the closest points to the decision boundary and define the separation.
Naive Bayes
How it works geometrically:
Uses Bayes' theorem with the naive assumption that features are independent given the class. Each class has its own (often Gaussian) distribution per feature; the overall likelihood is the product of 1D likelihoods. This leads to axis-aligned density contours and typically simple decision boundaries.