Two sample z-test
Hypothesis tests · Method and input reference
Two-sided; independent t uses Welch. Paired tests require matched observations. Permutation uses difference in means, 9,999 resamples and a fixed seed. Effect sizes use pooled sample SD. Synthetic example: Two independent blood-pressure cohorts: 120 and 96 people, with unequal variability; values in mmHg.
Open calculator · Compare methods in the decision matrix
Required inputs
- Observations — Numeric observations; preserve the row and column structure described above.
- Second sample — Numeric observations; preserve the row and column structure described above.
- Group 1 known SD — Enter the method parameter described above.
- Group 2 known SD — Enter the method parameter described above.
Review missing values and data coding before running. Sample inputs are synthetic teaching examples.
Implementation
Lifescio implements the method-specific formula using the listed SciPy distribution functions and NumPy array arithmetic. See method help for assumptions.
- scipy 1.15.3: scipy.stats.norm.sf
These are pinned library versions; saved results record the versions actually used at runtime.