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找到 36 个匹配主题
Empirical risk and loss functions
Distinguish the training objective from predictive performance.
适用条件
A labelled sample and a specified prediction task.
Linear regression as an optimisation problem
Connect regression coefficients to least squares.
适用条件
A linear predictor in specified features; squared loss.
Normal equations
Derive the least-squares stationarity condition in two ways.
适用条件
Unconstrained least squares with real A and b.
Orthogonal projection
Characterise the closest vector in a subspace.
适用条件
A finite-dimensional subspace of a Euclidean space.
Orthogonality and residuals
Express orthogonality using an inner product.
适用条件
The standard Euclidean inner product.
Vectors and linear combinations
Interpret a linear combination geometrically.
适用条件
Real, finite-dimensional vectors of compatible dimensions.
Column space, rank and nullity
Relate independent directions to uniqueness.
适用条件
Finite-dimensional real matrices.
Derivatives as local approximations
Use a derivative to predict a local change.
适用条件
Differentiability at the point; sufficiently small increments.
Logistic classification and likelihood
Relate a Bernoulli model to cross-entropy.
适用条件
Binary labels; independent observations conditional on inputs for the product likelihood.
Random variables and independence
Distinguish a random variable, a realisation and independence.
适用条件
A specified probability model and events with defined probabilities.
Gradients and local descent
Justify the negative gradient as a local descent direction.
适用条件
Differentiability, nonzero gradient and a sufficiently small positive step.
Gradient descent and learning rates
Explain an update rule and its convergence limitations.
适用条件
Ordinary gradient descent; distinguish its assumptions from other optimisers.
Regularisation and inductive bias
Explain how ridge regularisation changes the objective.
适用条件
Ridge with penalising all coefficients in the stated formula.
Validation, leakage and generalisation
Design an evaluation that respects how new data arrive.
适用条件
A defined target population and sampling or temporal structure.
Supervised-learning examination synthesis
Connect assumptions, objectives, optimisation and evaluation.
适用条件
State the task and data-generating constraints before selecting a method.
Existence and uniqueness
Separate a unique fit from unique coefficients.
适用条件
Finite-dimensional unconstrained least squares.
Conditioning and method selection
Distinguish mathematical existence from numerical reliability.
适用条件
Finite precision arithmetic; the condition-number identity assumes full column rank.
Least-squares examination synthesis
Combine solvability, geometry and rank in one argument.
适用条件
Real finite-dimensional least squares; distinguish exact and approximate fitting.
Sampling distributions
Distinguish data variation from estimator variation.
适用条件
A specified repeated-sampling scheme.
Bias, variance and mean squared error
Separate systematic error from sampling variation.
适用条件
Finite second moments for the estimator.
Standard errors and normal approximation
Identify the assumptions behind a mean interval.
适用条件
IID data with finite positive variance for the classical CLT; exact t inference additionally uses normal observations.
Maximum-likelihood estimation
Construct a likelihood and check its maximiser.
适用条件
A specified parametric model; independence when factorising the likelihood.
Confidence intervals and coverage
Interpret a confidence procedure under repeated sampling.
适用条件
The sampling model and interval construction must be specified.
Hypothesis tests and p-values
Interpret a p-value relative to a specified null model.
适用条件
A prespecified test statistic, null distribution and tail convention.
Type I error, power and multiplicity
Distinguish false rejection from sensitivity to an alternative.
适用条件
Power is evaluated at a specified alternative parameter value.
Statistical-inference examination synthesis
Connect an inferential claim to its estimand and assumptions.
适用条件
A defined estimand, sampling design and model.
Problem specifications and correctness
State valid inputs and the required output before choosing an algorithm.
适用条件
Explicit preconditions and a finite input representation.
Loop invariants
Prove a loop correct using an invariant.
适用条件
An invariant at a precisely stated program point and a terminating loop.
Induction and proof structure
State a base case and an inductive implication.
适用条件
An integer-indexed claim with an appropriate starting index.
Asymptotic complexity
State and justify an asymptotic resource bound.
适用条件
A specified input-size measure and cost model.
Recursive correctness and termination
Separate recursive meaning from termination.
适用条件
Recursive calls on strictly smaller cases under a well-founded measure.
Divide and conquer
Derive a recurrence from an algorithm structure.
适用条件
For the stated merge-sort recurrence, n is a power of two and merging is linear.
Greedy strategies and exchange arguments
Justify a greedy choice or find a counterexample.
适用条件
A specified optimisation problem; the example is unweighted interval scheduling, with compatibility allowing the next interval to start at the previous finish time.
Dynamic programming and state design
Define a sufficient state, recurrence and evaluation order.
适用条件
Positive integer denominations, a nonnegative integer amount and unlimited supply of each coin; states must retain information needed for future choices.
Algorithm examination synthesis
Present a complete algorithmic argument.
适用条件
Explicit input restrictions, cost model and optimisation objective.
