Stats 0.1.0 tests - CyrilB1531/lodestar GitHub Wiki
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Lodestar.Stats
Ten families of classical hypothesis test, at scipy.stats 1.18.0 parity.
Arrays in, a statistic and a p-value out; nothing is fitted, so every entry
point is static.
| test | what it asks | entry point |
|---|---|---|
| Student / Welch t | do two samples have the same mean? | TTest |
| Mann-Whitney U | the same question, assuming no shape | MannWhitney |
| Wilcoxon signed-rank | the same, on paired measurements | Wilcoxon |
| χ² | do counts match an expected distribution, or are two factors independent? | ChiSquare |
| Fisher exact | the same for a 2×2 table, at any sample size | FisherExact |
| Kolmogorov-Smirnov | do two samples share a distribution? | KolmogorovSmirnov |
| one-way ANOVA | do several groups share one mean? | OneWayAnova |
| Kruskal-Wallis | the same, assuming no shape | KruskalWallis |
| Shapiro-Wilk | could this sample be normal? | ShapiroWilk |
| Bonferroni / BH / BY | how many of these results are chance? | MultipleComparisons |
Every family but three returns the same two numbers, TestResult; a
t-test also carries its degrees of freedom (TTestResult), a
contingency table also carries the table independence would have produced
(Chi2ContingencyResult), and Kolmogorov-Smirnov also carries
where and in which direction the two samples parted furthest (KsResult).
| result | carries | returned by |
|---|---|---|
TestResult |
a statistic, a p-value | eight of the ten families |
TTestResult |
+ degrees of freedom, a confidence interval | TTest |
Chi2ContingencyResult |
+ degrees of freedom, the expected table | ChiSquare.Contingency |
KsResult |
+ where the gap was reached, and its sign | KolmogorovSmirnov |
Five small enums choose what a test asks, and how it answers when the exact and the approximate route disagree.
| option | chooses |
|---|---|
Alternative |
which tail the p-value covers |
Variance |
whether an independent-samples t-test pools the two variances |
Continuity |
whether a discrete statistic's normal approximation gets the half-unit correction |
ExactMethod |
the exact null distribution, its normal approximation, or a choice between them |
ZeroMethod |
what Wilcoxon does with a pair whose difference is exactly zero |
The hypothesis-testing guide says which
test answers which question, and the
Python equivalence table maps each scipy call to its
counterpart here.