Mathematical statistics: derivation and model criticism
Twenty-two lessons deriving estimators, tests, intervals and regression from probability models. Exact finite-sample results, regular asymptotic approximations and model-dependent decisions are distinguished. Mixed assessment, independent analysis and proof review remain separate requirements; topic coverage alone does not establish semester equivalence.
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Readiness and preparation
Check your starting point
Try these short questions on paper, then compare your reasoning. They are optional self-checks, not a placement score or a navigation requirement. Use a targeted review when useful and return with your browser’s Back control.
For independent Bernoulli(p) observations, what are the expectation and variance of their sample mean?
Estimator risk begins with a sampling distribution under stated assumptions.
Compare reasoning and find a refresher
The expectation is p and the variance is p(1−p)/n. Independence removes covariance terms; identical success probabilities make the common parameter p meaningful.
What is random in a frequentist confidence procedure?
Parameter, statistic and random interval have different roles in mathematical inference.
Compare reasoning and find a refresher
The data and resulting interval vary under repeated sampling; the target parameter is fixed. Coverage is a property of the procedure under a specified model, not a probability assigned to that fixed parameter after observing one interval.
Why does conditioning a square-integrable random variable reduce its mean squared prediction error?
Conditional expectation underlies Rao–Blackwell improvement and several statistical decompositions.
Compare reasoning and find a refresher
The conditional mean is the orthogonal squared-error predictor among functions of the conditioning information. Expanding the square yields an irreducible conditional-variance term plus the squared difference from that mean.