Statistics is the core of the site: how to reason from incomplete data without turning assumptions into decoration. This hub collects articles on inference, modelling, diagnostics, uncertainty and probability.

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Foundations

Probability, distributions, estimation, hypothesis testing and common errors.

Modelling and diagnostics

Regression, GLMs, Bayesian models, robust methods, survival analysis and model checking.

State Space Models and the Kalman Filter

State Space Models and the Kalman Filter

The Kalman filter is usually introduced as a tracking algorithm for spacecraft. It is more useful understood as the general engine for estimating hidden state from noisy observation.

Regime-Switching Models for Time Series

Regime-Switching Models for Time Series

A single model fitted across a recession and an expansion describes neither. Regime-switching models allow the dynamics themselves to change, with the regime inferred rather than assumed.

Nowcasting with Mixed-Frequency Data

Nowcasting with Mixed-Frequency Data

The quantity you care about arrives quarterly and two months late. Related indicators arrive daily. Nowcasting is the problem of estimating the present from what has already been published.

Interrupted Time Series and Causal Impact

Interrupted Time Series and Causal Impact

A intervention happened at a known date and you need its effect. There is no control group, only the series itself before and after, and the counterfactual has to be constructed.

Modelling Count Time Series

Modelling Count Time Series

Daily incident counts are integers, non-negative, often small, and correlated with yesterday. ARIMA assumes none of that and Poisson regression assumes independence.

Uncertainty and decision-making

Calibration, confidence intervals, prediction intervals, Bayesian decision theory and operational risk.

Modelling Count Time Series

Modelling Count Time Series

Daily incident counts are integers, non-negative, often small, and correlated with yesterday. ARIMA assumes none of that and Poisson regression assumes independence.

Outliers: A Detailed Explanation

Outliers: A Detailed Explanation

Outliers, or extreme observations in datasets, can have a significant impact on statistical analysis. Learn how to detect, analyze, and manage outliers effectively to ensure robust data analysis.