This GCSE Biology quiz is all about the range of data. In a scientific investigation, the range describes the maximum and minimum values of the independent or the dependent variables studied. It helps to detect any patterns in the data. Range is usually quoted as '10 mm to 70 mm' or '70 mm to 10 mm'. Top grade students would be using this to explain the limitations of their results, for example 'between 10 mm and 70 mm the pattern is ...'. They would then go on to say that it would be useful to conduct further work to investigate a higher and lower range.
In mathematics, the range of data is defined as the difference between the lowest number (minimum) and the highest number (maximum) in the data set and is useful when applied to the data obtained from repeating an experiment. The smaller the range of the repeats, the higher the precision of the experiment and the more reliable the data. Top grade candidates in science will be using mathematics to analyse their results. They could use the range to help their arguments for or against the reliability of their experiment.
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Take for example these two sets of data obtained by different groups of students carrying out the same experiment:
Team A: 12, 12, 10.5, 10, 12, 10, 12.5
Team B: 14, 11.5, 12, 9, 12, 10.5, 10
Each team of students carried out the experiment 7 times and by pure chance, both sets of results give the same mean value. The range of the data of team A is 2 (their maximum value is 12.5 and their minimum 10.5) but the range for team B is 5 (their maximum value is 14 and their minimum 9) so you can say that the results of team A are more precise. If the two teams were to carry out the same experiment once more, team A would be more likely to be closer to the mean value.
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