Quality control comprises both accuracy and precision.
Accuracy: refers to the closeness of the measured quantitative value to the reference value.
- Systematic errors will affect a system's accuracy.
- Bias is an estimate of systematic error.
Precision refers to the agreement of results upon replicate testing of a material or similar material under specified conditions.
- Random errors will affect a test system's precision
- Standard deviation and coefficient of variation are measures of imprecision.