# Glossary AQA.csv

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1. Define: Accuracy
A measurement result is considered accurate if it is judged to be close to the true value.
2. What is meant by Calibration
Applying a scale to a measuring instrument using a known reference value. For example, placing a thermometer in melting ice to see whether it reads zero, in order to check if it has been calibrated correctly.
3. What is meant by Data
Information, either qualitative or quantitative that has been collected.
4. What is a Measurement Error
The difference between a measured value and the true value.
5. What are Anomalies
Results that do not fit the pattern of data, are outside accepted uncertainty.
6. What is random error
These cause readings to be spread about the true value, due to results varying in an unpredictable way, from one measurement to the next.
7. Where do random erros occur?
Random errors are present when any measurement is made, and cannot be corrected.
8. How can random errors be reduced?
The effect of random errors can be reduced by making more measurements and calculating a new mean.
9. What is sysetmatic error?
These cause readings to differ from the true value by a consistent amount each time a measurement is made.
10. Where does systematic error occur?
Sources of systematic error can include the environment, methods of observation or instruments used.
11. How do we reduce systematic error?
Systematic errors cannot be dealt with by simple repeats. 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.
12. What is meant by a Zero error
When a reading should be zero, it actualy reads a value of greater than 0, or less than zero. E.g. an ammeter reads 0.1 amps when it has no cables attached to it.
13. What is meant by Evidence
Data which has been shown to be valid.
14. What is meant by a Fair test
A fair test is one in which only the independent variable has been allowed to affect the dependent variable.
15. What is meant by a Hypothesis
A proposal intended to explain certain facts or observations.
16. What is an Interval
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.
17. What is meant by Precision
Precise measurements are ones in which there is very little spread about the mean value. Precision depends only on the extent of random errors, it gives no indication of how close results are to the true value."
18. What is a Prediction
A prediction is a statement, suggesting what will happen in the future based on observation experience or a hypothesis.
19. What is meant by the Range
"The maximum and minimum values of the independent or dependent variables; important in ensuring that any pattern is detected.For example a range of distances may be quoted as either: "From 10cm to 50 cm"or"From 50 cm to 10 cm"
20. What is meant by Repeatable
A measurement is repeatable if the original experimenter repeats the investigation using the same method and equipment, and obtains the same results.
21. What is meant by Reproducible
"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. What is meant by the Resolution
This is the smallest change of the input, that gives an observable change to the output.
23. What is a Sketch graph
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.
24. What is meant by the True value
This is the value that would be obtained in an ideal measurement.
25. What is Uncertainty
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 at a level of confidenceof 95 %.
26. What is a Valid experiment
An experiment in which all the variables other than the dependent variable were controlled, therefore producing valid results.
27. What is a Valid conclusion
A conclusion supported by valid data, obtained from an appropriate experimental design and based on sound reasoning.
28. What is a Variable
These are physical, chemical or biological quantities or characteristics that can change. E.g. Force or temperature.
29. What is meant by the Categoric Variable
Categoric variables have values that are labels. Eg names of plants or types of material.
30. What is meant by the Continuous Variable
Continuous variables have values that are quantities. E.g. your height or number of bacteria.
31. What is meant by the Control Variable
A control variable is one that is kept the same because if it wasn't it would affect the experiment.
32. What is meant by the Dependent Variable
The dependent variable is the variable of which the value is measured for each and every change in the independent variable.
33. What is meant by Independent Variable
"The independent variable is the variable for which values are changed or selected by
 Author: McAuley ID: 155236 Card Set: Glossary AQA.csv Updated: 2012-05-23 07:31:18 Tags: McAuley ISA AQA GLOSSARY Folders: Description: McAuley ISA AQA GLOSSARY Show Answers: