3.1.2 - Definitions

Question 1

Measurement error?

Answer 1

The difference between a measured value and the true value.

Question 2

Anomalies?

Answer 2

These are values in a set of results which are judged not to be part of the variation caused by random uncertainty.

Question 3

Random error?

Answer 3

These cause readings to be spread about the true value, due to results varying in an unpredictable way from one measurement to the next.

Question 4

Systematic errors?

Answer 4

These cause reading to differ from the true value by a consistent amount each time a measurement is made.

Question 5

Zero error?

Answer 5

Any indication that a measuring system gives a false reading when the true value of a measured quantity is zero.

Question 6

Precision?

Answer 6

Precise measurements are ones in which there is very little spread about the mean value. Precision depends only on the extent of random errors - it gives no indication of how close results are to the true value.

Question 7

Repeatability?

Answer 7

A measurement is repeatable if the original experimenter repeats the investigation using the same method and equipment and obtains the same results.

Question 8

Reproducibility?

Answer 8

A measurement is reproducible if the investigation is repeated by another person, or by using different equipment or techniques, and the same results are obtained.

Question 9

Resolution?

Answer 9

The smallest change in the quantity being measured (input) of a measuring instrument that gives a perceptible change in the reading.

Question 10

Accuracy?

Answer 10

A measurement result is considered accurate if it is judged to be close to the true value.