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29 Cards in this Set
- Front
- Back
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Accuracy |
A measurement is said to be accurate when it is judged to be close to the true value. |
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Calibration |
Marking a scale on a measuring instrument. It involves establishing the relationship between the increments on a measuring instrument and the standard or reference values, which must be applied. |
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Data |
Information, either qualitative or quantitative, that has been gathered. |
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Errors |
See also uncertainties |
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Measurement error |
The difference between the measured value and the true value. |
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Anomalies |
Measurements that are judged not to be part of the variation caused by random uncertainty. |
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Random error |
An error that causes readings to be spread around the true value due to results varying unpredictably from one measurement to the next. They are present when any measurement is made, and cannot be corrected. However, their effect can be reduced by taking more measurements and calculating a new mean. |
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Systematic error |
An error that causes readings to differ from the true value by a consistent amount each time a measurement is made. These can be caused by observation methods, equipment and the environment. Systematic errors cannot be dealt with by simple repeats. If such an error is suspected, the experiment should be done again with a different method or equipment and the results compared. |
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Zero error |
When a measuring instrument gives a reading with no input. A zero error can be a source of systematic error. |
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Evidence |
Data which has been shown to be valid. |
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Fair test |
A test in which only the independent variable has been allowed to affect the dependent variable. |
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Hypothesis |
A proposal intended to explain facts or observations. |
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Interval |
The difference between readings |
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Precision |
Measurements are said to be precise when there is very little spread around the mean value. This depends on the extent of random errors and does not show the accuracy. |
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Prediction |
A statement suggesting what will happen in the future, based on observation, experience or a hypothesis. |
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Range |
The range is the maximum and minimum value of the independent/dependent variable. |
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Repeatable |
An experiment is said to be repeatable if the original investigator can do it again with the same equipment and method and get the same results. |
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Reproducable |
An experiment is said to be reproducable if another person can do it at another time, or with a different method or equipment, and get the same results. |
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Resolution |
The smallest scale division on an instrument or the smallest measurement it can take. |
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Sketch graph |
A line graph that shows the rough trend in the relationship between the two variables plotted. The axes must be labelled. |
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True value |
The value that would be obtained in an ideal measurement. |
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Uncertainty |
The interval within which the true value can be expected to lie, with a given level of confidence or probability. |
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Validity |
The suitability of the investigation to answer the question. |
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Valid conclusion |
A conclusion based on valid data, obtained from an appropriate experimental design and based on sound reasoning. |
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Categoric variable |
A variable that can only be a number of labelled categories. |
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Continuous |
A measurement that can be any value which can be obtained by counting or measurement. |
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Control variable |
In addition to the independent variable, this must be regulated in order to ensure nothing undesired affects the independent variable. |
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Dependent variable |
The value measured for each change in the dependent variable. |
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Independent variable |
The variable for which values are changed/selected by the investigator. |
