(1.2) Errors and Uncertainty

Question 1

What is a true value?

Answer 1

The value a measurement should be

Question 2

What is the observed value?

Answer 2

The measurement we take

Question 3

What is an error?

Answer 3

The uncertainty we have around our measurement

Question 4

How do we calculate our true value?

Answer 4

True value = observed value + error

Question 5

What is a systematic error?

Answer 5

It is an error that follows a set pattern (affects accuracy)

Question 6

What is a random error?

Answer 6

An Error that follows no set patterns (affects precision)

Question 7

What does accuracy mean?

Answer 7

How close a measurement is to the correct value for that measurement

Question 8

What does precision mean?

Answer 8

How close to each other the repeated measurements are

Question 9

What does repeatability mean?

Answer 9

A measurement is repeatable if the same person performing the same experiment with the same apparatus produces the same results

Question 10

What does reproducibility mean?

Answer 10

A measurement is reproductible if a different person preforms the same experiment with the same apparatus produces the same results

Question 11

What does resolution mean?

Answer 11

The resolution of a measuring instrument describes its maximum precision

Question 12

What does uncertainty mean?

Answer 12

A measure of how confident you can be in a measurement

Question 13

How do you reduce random errors?

Answer 13

Take at least 3 repeats, use computer loggers/ data to reduce human error and use appropriate equipment with the resolution required

Question 14

How to reduce systematic errors?

Answer 14

Calibrate the apparatus by measuring a known value, in radiation experiments correct for background radiation, read the meniscus at eye level and use controls in experiments