Coefficients-only calibrations

Some sensors — mainly ones sent to an outside lab — come back with a calibration certificate that states the calibration polynomial's coefficients directly, with no raw reference/measured data points included. For these, Open Gauge has a dedicated path so you don't have to fabricate fake data points just to record the result.

Using it

On an External calibration, checking "Coefficients only (no raw data)" in Step 1 replaces the wizard's raw-data step with a manual coefficient-entry form:

• Polynomial order (1–5) and its coefficients, entered in the same descending-power convention Open Gauge's own regression engine uses (highest degree first, constant term last).
• The valid range (min/max) the polynomial applies over.
• Optionally, "Uncertainty stated on certificate" — if the lab's certificate states an expanded uncertainty and coverage factor, enter them here to store them directly (rather than fabricating a fit-derived value), producing a single external_certificate_stated row in the uncertainty budget.

What's intentionally left blank

Because there's no raw data, Open Gauge doesn't compute (and doesn't display) a fit — this path deliberately leaves R², RMSE, the fit_residuals budget row, and, critically, the decision rule and conformity statement, all empty.

A conformity (pass/fail) statement requires an assessed error to compare against a spec (GUM §6.3, ISO/IEC 17025 §7.8.6) — a coefficients-only record has no assessed error, only the calibration function itself. So Open Gauge doesn't show or store a fabricated CONFORMS/DOES NOT CONFORM badge for these records. If you need a conformity statement, use a regular (non-coefficients-only) calibration with the actual raw data instead.

See Example 4 for a complete worked case, including what gets saved and displayed.