Applied Science Technology Practice
What this domain tests
This domain tests the technical judgment behind your work: measurement and uncertainty, units and significant figures, quality assurance and quality control, testing methods, sampling, and documentation of technical results. You should understand the difference between accuracy and precision, how systematic and random error differ, and how calibration and traceability support reliable measurements. Know the purpose of standards, tolerances, and specifications, and how to recognize when a test result is invalid because of a control failure or an out-of-calibration instrument.
Traps to watch for
Questions often swap accuracy and precision. Accuracy is closeness to the true value; precision is repeatability. A precise but biased instrument is still wrong. Watch for unit-conversion traps and for significant-figure errors; carrying too many digits suggests false confidence. Another trap is accepting a result that passed a test but failed a quality control check; QC failure invalidates the run regardless of the sample result. Be careful with questions that ask whether a method is "valid" when it is merely "standard."
Rule of thumb
Before trusting any number, ask three questions: was the instrument calibrated and traceable, did the QC pass, and are the units and significant figures correct? If any answer is no, the number is not reportable.
Worked example
A balance reads 12.50 g for a certified 10.00 g check weight. The instrument is precise but biased by +2.50 g. Correct response: halt use, recalibrate or repair, and re-run affected samples. Do not simply apply a mental correction.