
A classifier is two things at once: a probability ranker and a threshold, and almost every evaluation mistake comes from confusing the two. This episode is the model-agnostic ruler for measuring any classifier, from the confusion matrix up through ROC/AUC, PR curves, and calibration.
Logistic regression takes the same linear score from last episode, w dot x plus b, squashes it through a sigmoid into a probability, and trains it with cross-entropy, which turns out to be maximum likelihood for a Bernoulli label. It's a linear classifier and, quietly, a single neuron, the exact template every classification network stacks at its top.
Fit a line, read its coefficients, and understand what "fitting" actually does before we ever touch the calculus. This is the dot product that quietly becomes logistic regression, a neuron, and every neural network downstream.
The whole point of machine learning is generalization to unseen data, and the single habit that protects it is holding out a test set you never touch until the end. We walk the full workflow loop from problem framing to monitoring, and we make the train/test split and cross-validation concrete with scikit-learn.
Before you touch a model, you need fluency in arrays and dataframes. This episode covers vectorization, broadcasting, views versus copies, axis semantics, and the pandas selection and groupby muscle memory every later ML episode silently assumes.
Build the exact dev environment this course runs on (Python, virtual environments, notebooks, git, VS Code) and learn why three to five shipped, defensible GitHub projects open more doors than any stack of certificates.
Every machine learning model fits one of four boxes, defined by where the training signal comes from: a human answer key, no key at all, a delayed reward, or labels the data manufactures from itself. Get this taxonomy crisp and you can place any model in Phase 1 and ace the most common ML interview opener.
Seventy years of AI swing like a pendulum between hand-coded logic and learning from data, and every winter for one camp was the opening for the other. This episode traces that arc from myth and the Dartmouth workshop, through two funding collapses, to the transformer and today's agents.
AI is the goal, machine learning is the method, and deep learning is one branch, while statistics and data science overlap rather than nest inside. Get the mental map, the four learning paradigms, and the operator-versus-user thesis that the whole course is built on.