Description
Combine supplied standard uncertainties of a difference using an explicit correlation assumption.
Quality records separate measured results, reference values, acceptance rules, and supporting evidence. Arithmetic consistency and record coverage can be checked against supplied criteria without establishing traceability, approving a method, or deciding product conformity.
Combine supplied standard uncertainties of a difference using an explicit correlation assumption.
When to use this tool
Use it for qc reference uncertainty correlation flag when the required inputs and conventions are already available.
How to use the tool and how it works
- Enter resultUncertainty, referenceUncertainty, suppliedCorrelation, useCorrelation. Use the stated units and boundary conventions.
- Run the calculation. Correct any input error before interpreting a result.
- Read differenceUncertainty. Inspect any known, defined, inclusion, or boundary flags before interpreting numeric values.
Require nonnegative result and reference uncertainties and suppliedCorrelation within minus one through one. Use that correlation when useCorrelation is true, otherwise zero; calculate the standard uncertainty of their difference from uResult²+uReference²-2*rho*uResult*uReference using a stable hypot form.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| resultUncertainty | Result Uncertainty | Required. Finite number; minimum 0. |
| referenceUncertainty | Reference Uncertainty | Required. Finite number; minimum 0. |
| suppliedCorrelation | Correlation coefficient between minus one and one, validated even if ignored. | Required. Finite number; minimum -1; maximum 1. |
| useCorrelation | Use Correlation | Required. Boolean. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| differenceUncertainty | Standard uncertainty of the difference in the same units as the two input uncertainties. | Required. Finite number. |
{
"input": {
"resultUncertainty": 3,
"referenceUncertainty": 4,
"suppliedCorrelation": 1,
"useCorrelation": true
},
"output": {
"differenceUncertainty": 1
}
}Limitations and assumptions
- The correlation range is validated even when useCorrelation is false. The tool does not estimate correlation, degrees of freedom, coverage factors, or an expanded uncertainty.
- The field tables describe structural bounds; the mechanics also state cross-field requirements. Malformed input shapes, disallowed keys, and invalid domains cause input errors. Results must remain finite and within the declared output contract. A successful false flag or zero placeholder is distinct from an error.
- Numeric arithmetic uses binary floating point. Exact comparisons have no hidden tolerance or decimal rounding; negative zero is exported as zero. Decimal-text integer operations retain the exactness specifically stated above.
Alternative or Complementary methods
For qc reference uncertainty correlation flag, check the source records and the supplied rule before comparing the result with another method. Use a separate evidence or method review when arithmetic consistency alone cannot establish the required conclusion.
References
Similar or alternative tools
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