Laboratory Equipment Calibration Flashcards

Which statistical parameter is used to describe the spread of repeated calibration measurements around the mean?

Answer: Standard deviation

Standard deviation quantifies the dispersion of repeated measurements and is a key component in calculating measurement uncertainty.

ISO/IEC 17025 requires that calibration laboratories demonstrate competence through:

Answer: Proficiency testing and interlaboratory comparisons

ISO/IEC 17025 mandates participation in proficiency testing programs to objectively demonstrate measurement competence.

What is 'dead weight' testing used to calibrate in laboratory settings?

Answer: Pressure gauges and transducers

Dead weight testers use known masses on a piston-cylinder system to generate precise pressure values for calibrating pressure measurement instruments.

Which calibration interval strategy adjusts frequency based on actual instrument performance history?

Answer: Risk-based adaptive calibration intervals

Adaptive calibration intervals use historical as-found data to extend intervals for stable instruments and shorten them for drifting ones.

When expressing calibration results, the expanded uncertainty is typically reported at a confidence level of:

Answer: 95%

By convention (GUM), expanded uncertainty U = k × uc is reported at approximately 95% confidence, typically using a coverage factor k = 2.

A pipette calibrated to deliver 1.000 mL consistently delivers 0.985 mL. This represents a percent error of:

Answer: 1.5%

Percent error = |measured − true| / true × 100 = |0.985 − 1.000| / 1.000 × 100 = 1.5%.

Environmental conditions such as temperature and humidity must be monitored and recorded during calibration because:

Answer: They influence measurement results and form part of the uncertainty budget

Temperature, humidity, and atmospheric pressure affect instrument performance and are significant uncertainty contributors that must be documented.