keywords

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.

Question 3

Data

Answer 3

Information, either qualitative or quantitative, that has been collected.

Question 4

Uncertainty

Answer 4

The interval within which the true value can be expected to lie, with a given level of confidence or probability, eg “the temperature is 20 °C ± 2 °C.

Question 5

Validity

Answer 5

Suitability of the investigative procedure to answer the question being asked.

Question 6

measurement error

Answer 6

The difference between a measured value and the true value.

Question 7

anomalies

Answer 7

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

Question 8

random error

Answer 8

These cause readings to be spread about the true value, due to results varying in an unpredictable way from one measurement to the next.
Random errors are present when any measurement is made

Question 9

systematic error

Answer 9

These cause readings to differ from the true value by a consistent amount each time a measurement is made.
Sources of systematic error can include the environment, methods of observation or instruments used.

Question 10

Evidence

Answer 10

Data which has been shown to be valid.

Question 11

Fair test

Answer 11

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

Question 12

Hypothesis

Answer 12

A proposal intended to explain certain facts or observations.

Question 13

Interval

Answer 13

The quantity between readings, eg a set of 11 readings equally spaced over a distance of 1 metre would give an interval of 10 centimetres.

Question 14

Precision

Answer 14

Precise measurements are ones in which there is very little spread about the mean value.

Question 15

Prediction

Answer 15

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

Question 16

Range

Answer 16

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

Question 17

Repeatable

Answer 17

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

Question 18

Reproducible

Answer 18

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 19

Resolution

Answer 19

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

Question 20

Sketch graph

Answer 20

A line graph, not necessarily on a grid, that shows the general shape of the relationship between two variables. It will not have any points plotted and although the axes should be labelled they may not be scaled.

Question 21

True value

Answer 21

This is the value that would be obtained in an ideal measurement.

Question 22

Valid conclusion

Answer 22

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

Question 23

Variables

Answer 23

These are physical, chemical or biological quantities or characteristics.

Question 24

catgoric variables

Answer 24

Categoric variables have values that are labels. Eg names of plants or types of material.

Question 25

continuous variables

Answer 25

Continuous variables can have values (called a quantity) that can be given a magnitude either by counting (as in the case of the number of shrimp) or by measurement (eg light intensity, flow rate etc).

Question 26

control variables

Answer 26

A control variable is one which may, needs tone monitored as it may change the results

Question 27

dependent variable

Answer 27

The dependent variable is the variable of which the value is deliberately measured in the investigation

Question 28

independent variable

Answer 28

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

Question 29

Error

Answer 29

The difference between the measured value and the true value