CCT Measurement Uncertainty & Error Analysis 2

Question 1

Systematic errors in measurement are best described as:

Accepted Answer

Consistent, repeatable offsets in one direction that do not average out

Answer

Systematic errors are reproducible inaccuracies that consistently bias results in one direction and cannot be reduced by averaging — they must be identified and corrected.

Question 2

The most effective way to reduce the contribution of random errors to a measurement result is to:

Accepted Answer

Take multiple measurements and compute the mean

Answer

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.

Question 3

The resolution uncertainty contribution from a digital display device is typically estimated as:

Accepted Answer

Half the last significant digit divided by √3

Answer

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.

Question 4

What is 'expanded uncertainty' in a calibration report?

Accepted Answer

The combined standard uncertainty multiplied by a coverage factor to provide a stated confidence interval

Answer

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.

Question 5

Hysteresis error in a measuring instrument is caused by:

Accepted Answer

Differences in readings when approaching the same value from increasing versus decreasing directions

Answer

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.

(CCT) Certified Calibration Technician Practice Test

(CCT) Certified Calibration Technician Practice Test

CCT Measurement Uncertainty & Error Analysis 2