Measurement Uncertainty & Error Analysis Flashcards
7 cards from real CCT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Measurement Uncertainty & Error Analysis flashcards as text
Systematic errors in measurement are best described as:
Answer: Consistent, repeatable offsets in one direction that do not average out
Systematic errors are reproducible inaccuracies that consistently bias results in one direction and cannot be reduced by averaging — they must be identified and corrected.
The most effective way to reduce the contribution of random errors to a measurement result is to:
Answer: Take multiple measurements and compute the mean
Random errors are governed by statistics; taking multiple measurements and computing the mean reduces the standard uncertainty by 1/√n, where n is the number of observations.
The resolution uncertainty contribution from a digital display device is typically estimated as:
Answer: Half the last significant digit divided by √3
For a digital display, the resolution uncertainty is half the last significant digit (±0.5 LSD), modeled as a rectangular distribution, giving a standard uncertainty of (0.5 LSD)/√3.
What is 'expanded uncertainty' in a calibration report?
Answer: The combined standard uncertainty multiplied by a coverage factor to provide a stated confidence interval
Expanded uncertainty U = k × uc, where k is a coverage factor chosen to achieve a desired level of confidence, and is the value reported on calibration certificates.
Hysteresis error in a measuring instrument is caused by:
Answer: Differences in readings when approaching the same value from increasing versus decreasing directions
Hysteresis is the path-dependent behavior where an instrument gives different readings for the same measurand value depending on whether the measurement was approached from above or below.
Linearity error in an instrument refers to:
Answer: Deviation of the instrument's response from a best-fit straight line across its range
Linearity error is the maximum deviation of the actual output curve from a best-fit or terminal-based straight line over the full measurement range.
In the context of uncertainty analysis, sensitivity coefficients (∂f/∂xi) are used to:
Answer: Account for how much each input quantity influences the combined output uncertainty
Sensitivity coefficients represent the partial derivatives of the output with respect to each input variable, weighting each component's uncertainty by its influence on the final result.