Glossary of terms Flashcards
Accuracy:
A measurement result is considered accurate if it is judged to be close to the true value
Calibration:
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
Data:
Information, either quantitative or qualitative, that has been collected
Uncertainties:
The interval within which the true value can be expected to lie, with a given level of confidence or probability
Measurement error:
The difference between a measured value and the true value
Anomalies:
Values in a set of results which are judged not to be part of the variation caused by random uncertainty
Random error:
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
What types of errors can you have?
Measurement error Anomalies Random error Systematic error Zero error
Systematic error:
Cause readings to differ from the true value by a consistent amount each time a measurement is made
What can be the sources of systematic errors?
- the environment
- methods of observation
- instruments used
What can you do to deal with a suspected systematic error?
the data collection should be repeated using a different technique or a different set of equipment and the results compared
Zero error:
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
Evidence:
Data which has been shown to be valid
Fair test:
A fair test is one in which only the independent variable has been allowed to affect the dependent variable
Hypothesis:
A proposal intended to explain certain facts or observations
Interval:
The quantity between readings
Precision:
Precise measurements are ones in which there is very little spread around the mean value
-depends only on the extent of random errors
Prediction:
A prediction is a statement suggesting what will happen in the future, based on observation, experience or a hypothesis
Range:
The maximum and minimum values of the independent or dependent variables, important in ensuring that any pattern is detected
Repeatable:
A measurement is repeatable if the original experimenter repeats the investigation using same method and equipment and obtains the same results
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
Resolution:
The smallest change in the quantity being measured (input) of a measuring instrument that gives a perceptible change in the reading
Sketch graph:
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
True value:
The value that would be obtained in an ideal measurement
