Practical Definitions

Question 1

Accuracy

Answer 1

The measurement result is considered accurate if it is close to the true value of

Question 2

Anomalies

Answer 2

The values in a set of results which are caused by random uncertainty

Question 3

Measurement error

Answer 3

The difference between a measured value and the true value

Question 4

Random error

Answer 4

These cause readings to be spread about the true value due to results varying in an unpredictable way. The effect of random errors can be reduced by making more measures and calculating a mean

Question 5

Systematic error

Answer 5

These cause reading to differ from the true value by a consistent amount each time a measurement is made. They can be caused by the environment or equipment used . If there is a systematic error, the measurements should be taken again correctly

Question 6

Zero error

Answer 6

Any indication that a measuring system gives a false reading when the true value is 0. These may result from systematic uncertainty

Question 7

Uncertainty

Answer 7

The interval within which the true value can be expected to lie e.g. +- 2 degrees