Elamur Groupantsmlab-builtins-stats-ttests
The groupant beside mlab/src/builtins/stats.rs in the Mova repository: what the code computes, what it never does, how to go back from its outputs, its invariants, cost and checks.
Facts
Implementation material. A Mova code model describes this code at one source revision: partial models, finite checks and their stated scope. It is not a reviewed general exposition, and its labels are shown as written, never raised.
Components
| component | label | where |
|---|---|---|
| approximant | partial | approximant |
| ast | partial | ../syntax.json |
| cost | symbolic source derived | invariant |
| descriptant | present | descriptant |
| invariant | partial | invariant |
| tests | partial bounded parent evidence | tests |
Obernants
The typed relations around the forward model: the behaviour complement (what the code never does), the reverse reconstruction (every input compatible with an output) and specialised views.
| id | type | label | where |
|---|---|---|---|
behavior_complement | behavior_complement | partial source derived model | behavior_complement |
reverse_reconstruction | reverse_reconstruction | partial source derived model | reverse_reconstruction |
tail_duality | tail_duality | partial source derived model | tail_duality |
confidence_interval | confidence_interval | partial source derived model | confidence_interval |
branch_relation | branch_relation | partial source derived model | branch_relation |
resource_cost | resource_cost | partial source derived model | resource_cost |
Model text
descriptant
mlab-builtins-stats-ttests
test_opts checks Alpha before Tail; t_one removes NaNs, computes unbiased SD and SE, t=(mean-m0)/SE. t_two uses pooled or Welch variance. t_p guards NaN/nonpositive df then uses survival tail. Wrappers extract arguments first; ttest rejects incompatible paired lengths before options. Both wrappers parse options before checking the minimum cleaned sample count; verdict uses strict p<alpha.
Epoch 2026-10-31: isolated source-bound fragment over bytes [15577,25404); includes no claim beyond this relation. Source hash bdc3772b09d9113e108afa29e391fee97a5372caf9052bb1689996c41c94116f.
approximant
ttests: forward relation
test_opts checks Alpha before Tail; t_one removes NaNs, computes unbiased SD and SE, t=(mean-m0)/SE. t_two uses pooled or Welch variance. t_p guards NaN/nonpositive df then uses survival tail. Wrappers extract arguments first; ttest rejects incompatible paired lengths before options. Both wrappers parse options before checking the minimum cleaned sample count; verdict uses strict p<alpha.
Domain: Finite, well-shaped bounded observations unless branch explicitly describes NaN/Inf. Direct public chi2/OLS helpers assume dimensions not checked at every index; wrappers add validation.
Executable surrogate gap: no measured cheaper implementation with a useful scoped metric is supplied. Categorical/error/effect relations are exact obligations, not percent losses. Future numeric caps only1/2/5/10%.
invariant
ttests: invariant and cost
Left(t)=Right(-t), Both=2SF(abs(t)) capped1; fault substitutes Normal only.
Both CI uses tcrit(1-alpha/2); one-sided CI has one infinite endpoint. Reports do not validate independence/normality.
Scope-specific cost: T cores O(n+m) time and cleaned copies, option scan O(number of pairs), constant-size result and optional report.
models
behavior_complement
NaN p does not reject H0; printed nonreject text is not proof p>=alpha. Both-tail symmetric p cannot reveal t sign. Invalid option precedes insufficient-sample error.
reverse_reconstruction
Given t,df,p, compatible samples include all location/scale transforms preserving standardized effect; t alone loses raw observations. Paired differences admit common offsets to x,y.
tail_duality
Left(t)=Right(-t), Both=2SF(abs(t)) capped1; fault substitutes Normal only.
confidence_interval
Both CI uses tcrit(1-alpha/2); one-sided CI has one infinite endpoint. Reports do not validate independence/normality.
branch_relation
test_opts checks Alpha before Tail; t_one removes NaNs, computes unbiased SD and SE, t=(mean-m0)/SE. t_two uses pooled or Welch variance. t_p guards NaN/nonpositive df then uses survival tail. Wrappers extract arguments first; ttest rejects incompatible paired lengths before options. Both wrappers parse options before checking the minimum cleaned sample count; verdict uses strict p<alpha.
resource_cost
T cores O(n+m) time and cleaned copies, option scan O(number of pairs), constant-size result and optional report.
tests
Evidence boundary
See ../tests.md for the actual selected source test and mutant. These tests sample the file, not every fragment branch. NaN p does not reject H0; printed nonreject text is not proof p>=alpha. Both-tail symmetric p cannot reveal t sign. Invalid option precedes insufficient-sample error. Other branches here are source-derived and unexecuted unless the parent test explicitly calls them.
This page in Markdown → https://md.groupants.elamur.ai/free/en/mova/mlab/src/builtins/stats.rs.groupant/ttests.groupant/