Quality and production

Measurement uncertainty budget builder

Independent Type A/B budget with distributions, sensitivities, RSS, Welch–Satterthwaite and explicit k.

Measurement uncertainty budget builder

Independent Type A/B budget following the law of propagation of uncertainty: distributions, sensitivities, RSS, Welch–Satterthwaite and an explicit coverage factor k.

Project and measurand

Project name

Measurand

Result y

Result unit

Global coverage factor k

Project description

Budget components

Component 1

Name

Type

Distribution model

Uncertainty basis aᵢ

Component divisor dᵢ

Sensitivity coefficient cᵢ

Degrees of freedom νᵢ

Source

Include in budget

Type A denotes statistical evaluation. Enter an already evaluated uncertainty basis, not raw observations; this tool does not calculate s/√n. The entered value is already the standard uncertainty u(xᵢ); dᵢ = 1. Blank νᵢ means infinite degrees of freedom. The user enters finite νᵢ > 0; this tool does not calculate n−1 automatically.

Component 2

Name

Type

Distribution model

Uncertainty basis aᵢ

Component divisor dᵢ

Sensitivity coefficient cᵢ

Degrees of freedom νᵢ

Source

Include in budget

Type B denotes evaluation from other knowledge such as a specification or certificate. Type A/B does not itself change the aᵢ/dᵢ equation. Enter the limit half-width ±a; u(xᵢ) = a/√3. Do not enter a full resolution step r without converting a = r/2. Blank νᵢ means infinite degrees of freedom. The user enters finite νᵢ > 0; this tool does not calculate n−1 automatically.

Component 3

Name

Type

Distribution model

Uncertainty basis aᵢ

Component divisor dᵢ

Sensitivity coefficient cᵢ

Degrees of freedom νᵢ

Source

Include in budget

Type B denotes evaluation from other knowledge such as a specification or certificate. Type A/B does not itself change the aᵢ/dᵢ equation. The entered value is the component expanded uncertainty Uᵢ; enter its own divisor kᵢ. Blank νᵢ means infinite degrees of freedom. The user enters finite νᵢ > 0; this tool does not calculate n−1 automatically.

Project import and export

FormatProject file

CSV or JSON content

The example is ready. Select Calculate to create the budget, table and chart.

Model, scope and source

u(xᵢ) = aᵢ / dᵢ

uᵢ(y) = cᵢ · u(xᵢ)

u_c(y) = √Σ[uᵢ(y)]²

νeff = u_c⁴ / Σ(uᵢ⁴ / νᵢ)

U = k · u_c

Result interval: y − U … y + U

The model covers independent, uncorrelated inputs and first-order linear propagation only. Covariances and a correlation matrix are not supported.

The unit is presentation metadata. The user is responsible for making aᵢ and cᵢ consistent with the unit of y; this tool performs no dimensional analysis or conversion.

The user supplies global k. νeff does not choose k automatically, and k = 2 does not by itself mean an exact 95% confidence level.

The result is not an accredited certificate, calibration-model fit or conformity decision.

JCGM 100:2008 (GUM) · NIST Technical Note 1297

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Measurement uncertainty budget builder