Articles, newest first
ARIMAX Time Series: Comprehensive Guide
The ARIMAX model extends ARIMA by integrating exogenous variables into time series forecasting, offering more accurate predictions for complex systems.
Read article
The Null Hypothesis: Compatibility, Power, and Test Sensitivity
A null hypothesis is a model restriction, not a statement to be accepted when a p-value is large. Statistical tests measure compatibility through a chosen st...
Read article
ANOVA, Welch ANOVA, and Kruskal-Wallis: They Are Not Interchangeable
ANOVA and Kruskal-Wallis do not answer the same question under different assumptions. The choice should follow the estimand, design, variance structure, and ...
Read article
Cox Proportional Hazards: Interpretation and Diagnostics
The Cox model estimates covariate effects on the hazard without specifying the baseline hazard, but hazard ratios are not risk ratios and proportional hazard...
Read article
Residual Diagnostics: Diagnose the Assumption That Matters
Residual diagnostics should target specific model assumptions: conditional mean, variance, dependence, tail behavior, leverage, and influence. A normality te...
Read article
Choosing Statistical Tests: Start with the Estimand
Statistical test selection should begin with the estimand, study design, sampling structure, and error criterion. Flowcharts fail when they reduce those deci...
Read article
Time Series in Epidemiology: Surveillance, Forecasting, and Interventions
Epidemiological time series are shaped by transmission, reporting, interventions, seasonality, and observation processes. Forecasting and outbreak detection ...
Read article
Grace Hopper: Pioneer of Computer Science and Programming Languages
Grace Hopper revolutionized computer science by developing the first compiler and contributing to COBOL. Discover her groundbreaking work and her legacy in t...
Read article
Log-Rank Test: What It Tests and When It Loses Power
The log-rank test compares event incidence over risk sets through time. Proportional hazards makes it especially powerful, but it is not the validity assumpt...
Read article
Box-Cox Transformations: Model First, Transformation Second
Box-Cox is a transformation family inside a statistical model. It should not be used as a ritual for making raw data look normal, and changing the response s...
Read article