Measurements And Their Errors

Question 1

Define accuracy

Answer 1

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

Question 2

Define precision

Answer 2

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

Question 3

What is random error?

Answer 3

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

Question 4

What is systematic error?

Answer 4

Causes all readings to differ from the true value by a fixed amount. Systematic error cannot be corrected by repeat readings, instead a different technique or apparatus should be used

Question 5

What is meant by repeatable?

Answer 5

The same experimenter can repeat a measurement using the same method and equipment, and obtain the same value

Question 6

Define resolution

Answer 6

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

Question 7

What is uncertainty?

Answer 7

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