Analysis of covariance (ANCOVA)
Hypothesis tests · Method and input reference
Factors use numeric category codes. Factorial ANOVA includes all interactions and Type II sums of squares. ANCOVA uses outcome, group, covariate columns and common slopes. MANOVA uses outcome columns followed by one group column. Synthetic example: 180 adults: blood pressure, treatment group (0/1), then age covariate.
Open calculator · Compare methods in the decision matrix
When to consider it
- Compare group outcomes with a numeric adjustment covariate; assess equal-slope assumptions.
Assumptions and scope
- Observations must be independent between subjects; repeated rows from one subject are not independent samples.
- Use the outcome and predictor coding required by the calculator; review missing data and model diagnostics.
Required inputs
- Data: outcome(s), then factor(s), then covariate for ANCOVA — Numeric observations; preserve the row and column structure described above.
Review missing values and data coding before running. Sample inputs are synthetic teaching examples.
Implementation
Lifescio validates inputs and formats results; listed functions are the principal calculation routines, not an exhaustive transitive dependency list.
- statsmodels 0.14.4: statsmodels.formula.api.ols, statsmodels.stats.anova.anova_lm
These are pinned library versions; saved results record the versions actually used at runtime.