P3.2—Measurement quality and concordancy
- Syllabus
- 9701–2028–2029
- Objective
- P3.2
- Level
- AS
Accuracy, precision and concordance describe different aspects of data quality
Accurate results are close to the true value; precise results are tightly grouped; concordant titration titres agree closely, commonly within 0.10 cm³ in this course.
Read only to the precision supported by the apparatus and report colour, solubility and precipitate observations with specific language. Repeated agreement improves confidence but does not guarantee absence of systematic error.
Titres 24.10, 24.15 and 24.20 cm³ are concordant by the stated rule; 24.10, 24.80 and 24.90 cm³ are not, even if one value happens to be accurate.
Precision is not the same as accuracy, and writing extra decimal places does not create a better measurement.
ConceptA-Level CAIE Chemistry AS