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| Question | Answer |
| 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. This involves establishing the relationship between indications of a measuring instrument and standard or reference quantity values, which must be applied. For example, placing a thermometer in melting ice to see whether it reads zero, in order to check if it has been calibrated correctly. |
| Data | Information, either qualitative or quantitative, that has been collected. |
| Errors -Measurement Errors -Anomalies -Random Error -Systematic Error -Zero Error | -The difference between the measured value and the true value -These are values in a set of results which are judged not to be part of the variation caused by random uncertainty -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. 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. -Any indication that a measuring system gives a false reading when the true value of a measured quantity is zero, eg the needle on an ammeter failing to return to zero when no current flows. A zero error may result in a 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, eg a set of 11 readings equally spaced over a distance of 1 metre would give an interval of 10 centimetres. |
| 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. |
| 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. For example a range of distances may be quoted as either: "From 10cm to 50 cm" or "From 50 cm to 10 cm" |
| 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 | This is 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. It will not have any points plotted and although the axes should be labelled they may not be scaled. |
| True Value | This is the value that would be obtained in an ideal measurement |
| 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 confidence of 95 %. |
| Validity | Suitability of the investigative procedure to answer the question being asked. For example, 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 valid procedure if the temperature of the reactants was not controlled. |
| Valid Conclusion | A conclusion supported by valid data, obtained from an appropriate experimental design and based on sound reasoning. |
| Variables | These are physical, chemical or biological quantities or characteristics. - Categoric=Categoric variables have values that are labels. Eg names of plants or types of material. - Continuous=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). - Control=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.- dependent The dependent variable is the variable of which the value is measured for each and every change in the independent variable. - Independent=The independent variable is the variable for which values are changed or selected by the investigator |
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