APA Dictionary of Psychology

n. a measure of dispersion obtained by subtracting the lowest score in a distribution from the highest score. For example, if the highest score on a test is 100 and the lowest score is 10, then the range is (100 – 10) = 90 points. Because it describes a raw discrepancy between the low and high scores, range is generally perceived as less informative than other measures of dispersion, such as the standard deviation.