type b uncertainty

**Type B Uncertainty** is **measurement uncertainty evaluated by means OTHER than statistical analysis of observations** — determined from calibration certificates, manufacturer specifications, published data, engineering judgment, or theoretical analysis rather than from repeated measurement data. **Type B Sources** - **Calibration Certificate**: Uncertainty stated on the reference standard's certificate — inherited from the calibration lab. - **Manufacturer Specifications**: Gage accuracy, resolution, and environmental sensitivity specifications. - **Environmental**: Temperature coefficient × temperature variation — estimated, not measured. - **Distribution**: May be rectangular (uniform), triangular, or normal — the assumed distribution affects the standard uncertainty calculation. **Why It Matters** - **Complete Picture**: Type B captures systematic uncertainties that repeated measurements cannot reveal — e.g., calibration bias. - **Rectangular Distribution**: For uniform distributions: $u_B = a / sqrt{3}$ where $a$ is the half-width of the distribution. - **Combined**: Type B uncertainties are combined with Type A using RSS — treated identically in the uncertainty budget. **Type B Uncertainty** is **uncertainty from knowledge** — measurement uncertainty estimated from specifications, certificates, and engineering judgment rather than statistical data.