Practical terminology

Question 1

Accuracy

Answer 1

• Measure of the closeness of agreement between an individual test result and true value
• Accurate = close agreement with true value

Question 2

Anomaly (outlier)

Answer 2

Value in a set of results that is judged not to be part of the inherent variation

Question 3

Confidence

Answer 3

A qualitative judgement expressing the extent to which a conclusion is justified by the quality of euidence

Question 4

Error (of measurement)

Answer 4

The difference between an individual measurment and the true value of the quaantity being measured

Question 5

Precision

Answer 5

• Closeness of agreement between independent measurements obtained under same conditions
• Only dependent on the distribution of random errors (ie the spread or measurments)
• Does not relate to true value

Question 6

Repeatability

Answer 6

The precision obtained when measurement results are produced over a shorter timescale by one person or the same group using the same equipment in the same place

Question 7

Reproducibility

Answer 7

Precision obtained when measurment results are produced over a wider timescale by different people using equivalent equipment in different (but equivalent) places

Question 8

Resolution

Answer 8

The smallest change in the quantity being measured that can be detected by an instrument

Question 9

Uncertainty

Answer 9

An estimate attached to a measurement which characterises the range of values wuthin which the true value is expected to lie
Eg 44 +/- 0.4