1.1 measurements and their errors - definitions

Question 1

Accuracy

Answer 1

A measure of how close a measurement is to the true value

Question 2

Precision

Answer 2

A measure of how close a measurement is to the mean value. It only gives an indication of the magnitude of of random errors, not how close the data is to the true value

Question 3

Random error

Answer 3

Unpredictable variation between measurements that leads a spread of values about the true value. Random errors can reduced by taking repeat measurements

Question 4

Systematic error

Answer 4

causes all readings to differ from the true value by a fixed amount. Cannot be corrected by repeat measurements instead a new technique or apparatus must be used

Question 5

Repeatable

Answer 5

The same experimenter can repeat a measurement by using the same method with the same equipment and get the same value

Question 6

Reproducible

Answer 6

An experiment can be repeated by a different experimenter with different equipment and a different method and get the same answer

Question 7

Resolution

Answer 7

The smallest change in a quantity that causes a visible change in the reading that a measuring instrument records

Question 8

Uncertainty

Answer 8

The interval in which a value is said to lie within , with a given level of confidence