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Generalized estimating equations

regression

Estimate population-average associations for clustered or repeated responses.

Bayesian generalized mixed model

regression

Model subject-specific associations for repeated binary or count outcomes.

Descriptive statistics

descriptive

Use when the outcome/model family is not yet clear or the needed model is not implemented.

Welch's t-test

means

Compare a continuous outcome between exactly two independent groups without assuming equal variances.

Student's t-test

means

Compare two independent group means when equal variances are defensible.

Paired t-test

means

Compare two measurements from the same unit, person, or matched pair.

One-sample t-test

means

Compare one continuous variable against a known reference value.

Binomial test

categorical

Compare a binary outcome proportion against a specified reference proportion.

Mann–Whitney U

nonparam

Compare two independent groups when rank/ordinal behavior is more appropriate than means.

Wilcoxon signed-rank

nonparam

Compare paired ordinal or non-normal continuous measurements.

Kruskal–Wallis

nonparam

Compare three or more independent groups using ranks.

Friedman test

nonparam

Compare three or more paired or repeated measurements using ranks.

One-way ANOVA

means

Compare a continuous outcome across three or more groups.

Factorial ANOVA

means

Estimate main effects and interactions for multiple categorical factors.

Repeated-measures ANOVA

means

Compare three or more repeated measurements from the same unit.

ANCOVA

regression

Compare adjusted group means while controlling continuous covariates.

Pearson correlation

association

Measure linear association between two continuous variables.

Covariance

association

Describe how two numeric variables vary together in their original units.

Spearman correlation

association

Measure monotone association using ranks.

Kendall's tau

association

Measure ordinal or monotone association with a rank-based coefficient robust to small samples.

Point-biserial correlation

association

Measure association between one continuous variable and one binary variable.

Eta correlation ratio

association

Measure association between a continuous variable and a categorical grouping variable.

Partial correlation

association

Measure association between two continuous variables after linear adjustment for covariates.

Chi-square test

categorical

Test association between two categorical variables.

Fisher's exact test

categorical

Analyze a small 2x2 contingency table.

McNemar's test

categorical

Compare paired binary responses.

Linear regression (OLS)

regression

Model a continuous outcome with one or more predictors.

Logistic regression

regression

Model a binary outcome with one or more predictors.

Ridge regression

regression

Fit a linear regression when predictors are correlated and coefficient shrinkage is useful.

Lasso regression

regression

Fit a linear regression with coefficient shrinkage and possible variable selection.

Poisson regression

regression

Model count outcomes or rates.

Principal component analysis (PCA)

unsupervised

Reduce several correlated numeric features to a smaller set of variance directions.

K-means clustering

unsupervised

Explore whether observations form compact groups across several numeric features.

Exploratory factor analysis

unsupervised

Estimate latent factors that explain correlations among observed numeric variables.

Reliability analysis (Cronbach's alpha)

unsupervised

Assess the internal consistency of multiple items intended to measure one construct.

Hierarchical clustering

unsupervised

Explore nested group structure without fixing a cluster count in advance.

ROC analysis

association

Evaluate how a numeric score separates a binary outcome across thresholds.

Power and sample-size calculation

means

Plan sample size or estimate power for a mean comparison.

Kaplan–Meier + log-rank

survival

Compare survival curves between groups.

Cox proportional hazards

survival

Model time-to-event outcomes with covariates.

Linear mixed-effects model

regression

Model continuous outcomes with repeated or clustered observations.

Cohen's kappa

categorical

Measure agreement between two categorical ratings of the same observations.

Fleiss' kappa

categorical

Measure categorical agreement across three or more raters.

Intraclass correlation (ICC)

association

Assess absolute agreement among numeric ratings or repeated measurements.

Equivalence test (TOST)

means

Test whether a two-group mean difference is small enough to be practically equivalent.

Moderation analysis

regression

Test whether one numeric predictor changes the association of another with an outcome.

Mediation analysis

regression

Estimate an indirect association through a numeric mediator.

Multinomial logistic regression

regression

Model an unordered categorical outcome with three or more levels.