Key maths words and phrases

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 0°C, in order to check if it has been calibrated correctly.

Data: Information, either qualitative or quantitative, that has been collected.

Errors: See also uncertainties.

Evidence: Data which has been shown to be valid.

Hence: Use results found or given earlier in the question.

Hence, or otherwise: Any correct method is acceptable, but results found or given earlier in the question could be useful.

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.

Practical or ‘in context’ interpretation: Where a question asks for a practical interpretation, it specifically indicates that the answer should be phrased in context ie referring to the scenario given in the question rather than in general terms.

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

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.

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 10 cm to 50 cm’ or ‘From 50cm to 10cm’

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.

Scalar: A scalar is a quantity that has magnitude only.

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: These are physical, chemical or biological quantities or characteristics.

Vector: A vector is a quantity that has magnitude and direction.