Key Terms

Question 1

Validity

Answer 1

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

Question 2

True value

Answer 2

The value that would be obtained in an ideal measurement. With the exception of physical constants the true value is considered unknowable.

Question 3

Accuracy

Answer 3

A measurement is considered accurate if it is close to the true value. It cannot be quantified and is influenced by random and systematic errors.

Question 4

Precision

Answer 4

Denotes the closeness and agreement (consistency) between repeatedly measured values.

Question 5

Repeatability

Answer 5

A measurement is repeatable when similar results are obtained by students of the same group using the same method.

Question 6

Reproducibility

Answer 6

A measurement is reproducible when similar results are obtained by students of a different group using a different method.

Question 7

Uncertainty

Answer 7

The interval in which the true value can be considered to lie.

Question 8

Error

Answer 8

The difference between the measured value and true value.

Question 9

Resolution

Answer 9

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

Question 10

Significant figures (SF)

Answer 10

The number of SF depends upon the resolution of the measuring instruments used and is usually the same as the instrument with the fewest SF in its reading.