Glossary of terms

Question 1

Accuracy:

Answer 1

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

Question 2

Calibration:

Answer 2

Marking a scale on a measuring instrument
-involves establishing the relationship between indications of a measuring instrument and standard or reference quantity values, which must be applied

Question 3

Data:

Answer 3

Information, either quantitative or qualitative, that has been collected

Question 4

Uncertainties:

Answer 4

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

Question 5

Measurement error:

Answer 5

The difference between a measured value and the true value

Question 6

Anomalies:

Answer 6

Values in a set of results which are judged not to be part of the variation caused by random uncertainty

Question 7

Random error:

Answer 7

Cause readings to be spread about the true value, due to results varying in an unpredictable way from one measurement to the next
-they cannot be corrected, they can be reduced by making more measurements and taking a mean

Question 8

What types of errors can you have?

Answer 8

Measurement error
Anomalies
Random error
Systematic error
Zero error

Question 9

Systematic error:

Answer 9

Cause readings to differ from the true value by a consistent amount each time a measurement is made

Question 10

What can be the sources of systematic errors?

Answer 10

• the environment
• methods of observation
• instruments used

Question 11

What can you do to deal with a suspected systematic error?

Answer 11

the data collection should be repeated using a different technique or a different set of equipment and the results compared

Question 12

Zero error:

Answer 12

Any indication that a measuring system gives a false reading when the true value of a measured quantity is zero
-it may result in systematic uncertainty

Question 13

Evidence:

Answer 13

Data which has been shown to be valid

Question 14

Fair test:

Answer 14

A fair test is one in which only the independent variable has been allowed to affect the dependent variable

Question 15

Hypothesis:

Answer 15

A proposal intended to explain certain facts or observations

Question 16

Interval:

Answer 16

The quantity between readings

Question 17

Precision:

Answer 17

Precise measurements are ones in which there is very little spread around the mean value
-depends only on the extent of random errors

Question 18

Prediction:

Answer 18

A prediction is a statement suggesting what will happen in the future, based on observation, experience or a hypothesis

Question 19

Range:

Answer 19

The maximum and minimum values of the independent or dependent variables, important in ensuring that any pattern is detected

Question 20

Repeatable:

Answer 20

A measurement is repeatable if the original experimenter repeats the investigation using same method and equipment and obtains the same results

Question 21

Reproducible:

Answer 21

A measurement is reproducible if the investigation is repeated by another person or by using different equipment or techniques and the same results are obtained

Question 22

Resolution:

Answer 22

The smallest change in the quantity being measured (input) of a measuring instrument that gives a perceptible change in the reading

Question 23

Sketch graph:

Answer 23

A line graph, not necessarily on a grid, that shows the general shape of the relationship between two variables
-no points plotted, axes labelled but not necessarily scaled

Question 24

True value:

Answer 24

The value that would be obtained in an ideal measurement

Question 25

validity:

Answer 25

Suitability of the investigative procedure to answer the question being asked

Question 26

Valid conclusion:

Answer 26

A conclusion supported by valid data, obtained from an appropriate experimental design and based on sound reasoning.

Question 27

Variables:

Answer 27

Physical, chemical or biological quantities or characteristics

Question 28

What are the different types of variables?

Answer 28

Categoric variables
Continuous variables
Control variables
Dependent variables
Independent variables

Question 29

Categoric variables:

Answer 29

Categoric variables have values that are labels

Question 30

Continuous variables:

Answer 30

Continuous variables can have values (called a quantity) that can be given a magnitude either by counting or by measurement

Question 31

Control variables:

Answer 31

A control variable is one which may, in addition to the independent variable, affect the outcome of the investigation and therefore has to be kept constant or at least monitored

Question 32

Dependent variable:

Answer 32

The variable of which the value is measured for each and every change in the independent variable

Question 33

Independent variable:

Answer 33

The variable for which values are changed or selected by the investigator