CCT Measurement Uncertainty & Error Analysis 3

Question 1

What is an uncertainty budget in calibration?

Accepted Answer

A tabulated list of all uncertainty sources with their magnitudes and combined contribution

Answer

An uncertainty budget systematically lists every source of uncertainty, its magnitude, distribution type, sensitivity coefficient, and contribution to the combined standard uncertainty.

Question 2

Repeatability in measurement is defined as:

Accepted Answer

Closeness of agreement between repeated measurements under the same conditions in a short time period

Answer

Repeatability describes the closeness of agreement among successive measurements of the same measurand carried out under identical conditions (same operator, instrument, location, and time).

Question 3

Reproducibility in measurement differs from repeatability in that it:

Accepted Answer

Assesses agreement under varied conditions such as different operators, locations, or instruments

Answer

Reproducibility evaluates measurement agreement when one or more conditions are changed (different operator, lab, or equipment), making it a broader measure of consistency than repeatability.

Question 4

The Welch-Satterthwaite equation in uncertainty analysis is used to:

Accepted Answer

Calculate the effective degrees of freedom for the combined uncertainty

Answer

The Welch-Satterthwaite formula calculates the effective degrees of freedom of the combined uncertainty, which is needed to determine the appropriate coverage factor for a given confidence level.

Question 5

Guard bands in calibration decision-making are used to:

Accepted Answer

Reduce the acceptance zone to account for measurement uncertainty and control false acceptance risk

Answer

Guard bands narrow the acceptance zone by the measurement uncertainty to reduce the probability of accepting out-of-tolerance instruments (false acceptance), as described in ILAC-G8 and ASME B89.7.3.1.

(CCT) Certified Calibration Technician Practice Test

(CCT) Certified Calibration Technician Practice Test

CCT Measurement Uncertainty & Error Analysis 3