AQA specific vocabulary

• Accuracy 


  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.
• Data


  Information, either qualitative or quantitative, that has been collected.
• Measurement error


  The difference between a measured value and the true value.
• Amomalies


  Values in a set of results which are judged not to be part of the variation caused by random uncertainty.
• 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:

  they are present when any measurement is made, and cannot be predicted.
• Systematic error


  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.
• Zero error


  Any indication that a measuring system gives a false reading when the true value of a measured quantity is zero, a zero error may cause systematic uncertainty.
• Evidence 


  Data which has been shown to be valid.
• Fair test

  A test in which 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 about the mean value.
• Prediction

  A statement suggesting what will happen in the future, based on observation, experience or hypothesis.
• Range


  The maximum and minimum values of the independent or dependent variables, important in ensuring that any pattern is detected.
• Repeatable

  The original experimenter repeats the investigation using the same method and equipment and obtains the same results.
• Reproducible


  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 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, within a given level of confidence or probability.
• Validity


  Suitability of the investigation procedure to answer the question being asked.
• Valid conclusion


  A conclusion supported by valid data, obtained from an appropriate experimental design and based on sound reasoning.