Verification
9/9 calculation tests · Production surface contract 4/4
- Golden tests 0 / 0
- Boundary tests 6 / 6
- Property tests 3 / 3
- Production surface contract 4 / 4
}
- Engine tested Yes
- Source checked Yes
- Artifact integrity PASS
- Production attestation Embedded snapshot: STALE · Last attested schema matched 1.0.0 snapshot / local build · Semantic contract ✓ · Last attestation PASS · current evidence changed · re-attestation required · Public/cache ✓ · Origin ✓ · Live production status PASS (0 stale; 164 CURRENT) @ 2026-09-16T06:44:24.909Z
- Semantic contract PASS
- Evidence attested at 2026-09-16T06:44:24.203Z
- Last production check 2026-09-16T06:44:24.203Z
- Public / cache PASS
- Origin PASS
- Supplemental domain review Not performed
- Named expert review Not performed
- release artifacts aligned PASS
- schema valid input executes PASS
- engine success output validates schema PASS
- schema rejects incomplete input PASS
Fingerprint sha256:a2f052d317354a8445116f83db295918471d140482da7c1858d596fae86f0577
Input schema sha256:5002f38c117712a48a9de76599e4d9890cf3171eb7c59b0438ce12b96d629b39 · Output schema sha256:a457b8d5978d22bd3d5cc7a1fed8e64b731c7598b691339218cd768c1cea6fff · Build-time SHA-256 digests prove published artifacts agree with each other (release_integrity.scope=workspace). Production attestation GETs canonical URLs twice (public/cached view and origin), including Capability HTML, via npm run attest:production --write
(published at /.well-known/calculatorx-production-attestation.json) and fails if the public Capability page advertises a different calculation_version. This is artifact consistency, not an independent immutable release log.
Engine identity and declared limitations.
- Tool
- cochran
- Engine
- cochran
- Engine build
- 2026-09-16
- Evidence core
- 2026-09-16T21:07:40.795Z
- Rendered
- 2026-09-16T22:38:08.855Z
- Last reviewed
- —
Assumptions
- ISO 5725-2 Cochran C = s_max² / Σ s_i² from k≥2 stated laboratory sample standard deviations. k=1 is rejected.
- s_i ≥ 0. All-zero s is rejected (Σ s² must be > 0).
- Not pooled s_p, not Hartley's F_max, and not a tabulated Ccrit pass/fail.
Limitations
- Takes stated laboratory s_i — not a sample of observations
- k=1 is rejected so this cannot wrap identity C=1
- All-zero s is rejected (Σ s² must be > 0)
- Does not compare C to a tabulated Ccrit(p, n, α)
- Not pooled s_p and not Hartley's F_max
Sources
Standards and references supporting this tool specification. Methods are listed separately — they are algorithms, not bibliographic sources.
- ISO 5725-2 — Repeatability and reproducibility of standard measurement methods — Cochran's C test
Supports: C = s_max² / Σ s_i² is the test statistic for an unusually large laboratory repeatability variance. Critical values depend on p, n, and α and are not applied here.
- ISO 5725-1 — Accuracy (trueness and precision) of measurement methods and results — Repeatability standard deviation s_r
Supports: This page takes already-stated laboratory s_i. It does not estimate s_r from a collaborative-study table.
Published checks
Golden, boundary, and property cases included in this evidence build.
| ID | Kind | Status | Detail |
|---|
boundary-coch | boundary | pass | Expected C=0.5 · s_max=5 · k=3 · Actual C=0.5 · s_max=5 · k=3 |
boundary-coch-equal | boundary | pass | Expected C=0.5 · Actual C=0.5 · s_max=5 · k=2 |
boundary-coch-zero-one | boundary | pass | Expected C=1 · Actual C=1 · s_max=5 · k=2 |
boundary-coch-one | boundary | pass | Expected VALUE_OUT_OF_RANGE · Actual VALUE_OUT_OF_RANGE |
boundary-coch-allzero | boundary | pass | Expected VALUE_MUST_BE_POSITIVE · Actual VALUE_MUST_BE_POSITIVE |
boundary-coch-missing | boundary | pass | Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT |
property-coch | property | pass | 0.5 |
property-coch-equal | property | pass | 0.5 |
property-coch-alias | property | pass | 0.5 |
