Public evidence

engineering.measurement.precision

Machine-checked verification for calculation version 1.0.0 · tier engine_tested

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Verification

11/11 calculation tests · Production surface contract 4/4

Golden tests 0 / 0
Boundary tests 6 / 6
Property tests 5 / 5
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 sha256:4f7c98f6d836e8af1fef2609fa8b62d7332ac5c035ea1115ab7d21ba5540519d

Input schema sha256:65d9410031cef6fc8f33b821bcdad9be113c801be3440d3d9f3ebe8473ea5037 · Output schema sha256:7329792b52470abac7c43524f2e4abc6e0dad9123efa21b442d0d0191607e618 · 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.

Build & scope

Engine identity and declared limitations.

Tool: precision
Engine: precision
Engine build: 2026-09-15
Evidence core: 2026-09-15T13:27:56.944Z
Rendered: 2026-09-16T22:03:43.738Z
Last reviewed: —

Assumptions

ISO 5725 repeatability: s from summarizeSample, CV = s/|x̄| when x̄ ≠ 0, r = 2.8·s.
Not Type A u_A = s/√n, not Gauge R&R EV, and not percent CV (×100).

Limitations

r = 2.8·s is the ISO 5725 conventional repeatability limit, not coverage factor k
Does not report Type A u_A = s/√n
Not Gauge R&R repeatability (EV)
CV is not multiplied by 100; CV is undefined when x̄ = 0

Sources

Standards and references supporting this tool specification. Methods are listed separately — they are algorithms, not bibliographic sources.

ISO 5725-1 — Accuracy (trueness and precision) of measurement methods and results — Precision as repeatability; repeatability limit r = 2.8 σ_r
Supports: This page reports sample s and the conventional r = 2.8·s; it does not report a between-laboratory R
JCGM 200:2012 — International vocabulary of metrology (VIM) — 2.15 measurement precision
Supports: Precision is closeness of agreement under specified conditions, quantified here by s and CV

Published checks

Golden, boundary, and property cases included in this evidence build.

ID	Kind	Status	Detail
`boundary-prec`	boundary	pass	Expected s=1 · r=2.8 · cv=0.125 · xbar=8 · Actual n=3 · s=1 · cv=0.125 · r=2.8 · xbar=8 · ddof=1 · factor=2.8
`boundary-prec-span`	boundary	pass	Expected s=2 · r=5.6 · Actual n=3 · s=2 · cv=0.3333333333333333 · r=5.6 · xbar=6 · ddof=1 · factor=2.8
`boundary-prec-flat`	boundary	pass	Expected s=0 · r=0 · cv=0 · Actual n=3 · s=0 · cv=0 · r=0 · xbar=8 · ddof=1 · factor=2.8
`boundary-prec-cvnull`	boundary	pass	Expected r=2.8 · Actual n=3 · s=1 · r=2.8 · xbar=0 · ddof=1 · factor=2.8
`boundary-prec-n1`	boundary	pass	Expected VALUE_OUT_OF_RANGE · Actual VALUE_OUT_OF_RANGE
`boundary-prec-missing`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`property-prec`	property	pass	2.8
`property-prec-span`	property	pass	5.6
`property-prec-flat`	property	pass	0
`property-prec-cvnull`	property	pass	null
`property-prec-alias`	property	pass	2.8