Uncertainties and practical work

Question 1

Define validity

Answer 1

A measurement is valid if it measures what it is supposed to be measuring

Question 2

Define True value

Answer 2

The value that would have been obtained in an ideal measurement

Question 3

Accuracy

Answer 3

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

Question 4

Define precision

Answer 4

A quality denoting the closeness of agreement (consistency) between values obtained by repeated measurement

Question 5

Define Uncertainty

Answer 5

The interval within which the true value can be considered to lie with a given level of confidence or probability

Question 6

Define Error

Answer 6

The difference between the measurement result and the true value

Question 7

Define Resolution

Answer 7

The smallest measuring interval and the source of uncertainty in a single reading.

Question 8

How do you calculate percentage uncertainty?

Answer 8

Percentage uncertainty = (Uncertainty of measurement/Measurement taken) × 100%

Question 9

What is the uncertainty when measurements are added together?

Answer 9

The sum of he absolute uncertainties

Question 10

What is the uncertainty when measurements are multiplied together?

Answer 10

The sum of the percentage uncertainties