Probability

Inverting conditional probabilities: $P(H \mid E) = P(E \mid H)P(H)/P(E)$ — and why ignoring the prior (base rate) is the single most common probability error in interviews and in production

Bernoulli, binomial, Poisson, normal, and exponential — what data-generating story each one tells, and how to recognize which one an interview question is secretly about

Pick the parameter value that makes the observed data most probable — the single principle behind sample means, logistic regression, and cross-entropy loss