# AQA Key Terms Flashcards

1
Q

Define accuracy

A

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

2
Q

Define calibration

A

Marking a scale on a measuring instrument

3
Q

Define data

A

Information, either qualitative or quantitative, that has been collected

4
Q

Define measurement error

A

The difference between a measured value and the true value

5
Q

Define anomaly

A

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

6
Q

Define random error

A

Errors that cause readings to be spread about the true value, due to results varying in an unpredictable way from one measurement to the next.

7
Q

When are random errors present?

A

Random errors are present when any measurement is made, and cannot be corrected

8
Q

How can you reduce the effect of random errors?

A

The effect of random errors can be reduced by making repeat measurements and calculating a new mean

9
Q

Define systematic error

A

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

10
Q

What are sources of systematic errors?

A

Sources of systematic error can include the environment, methods of observation or instruments used

11
Q

Can systematic errors be dealt with via repeats?

A

No

12
Q

What should be done if a systematic error is suspected?

A

If a systematic error is suspected, the data collection should be repeated using a different technique or a different set of equipment, and the results compared.

13
Q

Define zero error

A

Any indication that a measuring system gives a false reading when the true value of a measured quantity is zero

14
Q

Define evidence

A

Data which has been shown to be valid

15
Q

Define hypothesis

A

A proposal intended to explain certain facts or observations.

16
Q

Define interval

A

17
Q

Define precision

A

Precise measurements are ones in which there is very little spread about the mean value. Repeat readings should be very similar to each other

18
Q

Can precision give an indication how accurate data is?

A

No. Precision depends only on the extent of random errors – it gives no indication of how close results are to the true value.

19
Q

Define prediction

A

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

20
Q

Define range

A

The maximum and minimum values of the independent or dependent variables

21
Q

Define reproducible

A

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.

22
Q

Define repeatable

A

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

23
Q

Define resolution

A

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

24
Q

What is a sketch graph?

A

A line graph, not necessarily on a grid, that shows the general shape of the relationship between two variables.

25
Q

Does a sketch graph need a scale or plotted points?

A

No. It will not have any points plotted and although the axes should be labelled they may not be scaled.

26
Q

Define true value

A

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

27
Q

Define uncertainty

A

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

28
Q

Define validity

A

Suitability of the investigative procedure to answer the question being asked. Only the 1 independent variable has been changed

29
Q

Define valid conclusion

A

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

30
Q

Define variables

A

These are physical, chemical or biological quantities or characteristics.

31
Q

Define categoric variable

A

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

32
Q

Define continuous variable

A

Continuous variables can have any numerical value

33
Q

Define control variable

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.

34
Q

Define independent variable

A

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

35
Q

Define dependent variable

A

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

36
Q

What word is udes to describe a measurement close to the true value?

A

Accurate

37
Q

Placing a thermometer in melting ice to check whether it reads 0 °C is an example of ?

A

Checking calibration

38
Q

What term do we use for information that we have collected?

A

Data

39
Q

What is the term for the difference between the measured value and the true value

A

Measurement error

40
Q

What do we call values that are not close to the true value and out of the range of uncertainty?

A

Anomalies

41
Q

What type of error causes readings to differ from the true value by a consistent amount each time a measurement is made?

A

Systematic error

42
Q

If the needle of an ammeter fails to return to 0 what type of error is this?

A

Zero error

43
Q

If our data is shown to be valid what do we call it?

A

Evidence

44
Q

What do we call a proposal to explain certain facts or observations?

A

A hypothesis

45
Q

What is the word for the quantity between readings?

A

Interval

46
Q

If all of my results are very close to my mean value I can say they are what?

A

Precise

47
Q

What do I call a statement suggesting what will happen in the future, based on observation, experience or a hypothesis.

A

A prediction

48
Q

If I said my data was 0-50cm what am I giving you?

A

The range

49
Q

If you repeat an experiment with the same method/equipment and get the same results you can say your data is what?

A

Repeatable

50
Q

If someone else repeats your experiment and gets the same results you can say your data is what?

A

Reproducible

51
Q

If you repeat an experiment with different equipment or a different technique and get the same results you can say your data is what?

A

Reproducible

52
Q

What is the word for the smallest change in quantity an instument can measure?

A

Resolution

53
Q

What do we call the the value that would be obtained in an ideal measurement?

A

The true value

54
Q

An investigation to find out if the rate of a chemical reaction depended upon the concentration of one of the reactants would not be a _______ procedure if the temperature of the reactants was not controlled.

A

Valid

55
Q

What type of variable is type of plant?

A

Categoric

56
Q

What type of variable is height?

A

Continuous

57
Q

In an investigation to find out if the rate of a chemical reaction depended upon the concentration of one of the reactants, what type of variable is temperature?

A

Control

58
Q

In an investigation to find out if the rate of a chemical reaction depended upon the concentration of one of the reactants, what type of variable is concentration?

A

Independent

59
Q

In an investigation to find out if the rate of a chemical reaction depended upon the concentration of one of the reactants, what type of variable is the rate?

A

Dependent

60
Q

What is the name for the variable that the investigator changes?

A

Independent variable

61
Q

What is the name for the variable that the investigator measures?

A

Dependent variable

62
Q

What is the name for the variable that the investigator keeps the same or monitors?

A

Control variable

63
Q

How can uncertainty be calculated for repeat readings?

A

Range/2