What is the purpose of the range, and how is it determined in a distribution of scores?Measures of dispersion, or measures of variability, are descriptive statistical techniques conducted to identify individual differences of the scores in a sample. These techniques give some indication of how scores in a sample are dispersed, or spread, around the mean. The measures of dispersion indicate how different the scores are or the extent that individual scores deviate from one another. If the individual scores are similar, dispersion or variability values are small and the sample is relatively homogeneous, or similar, in terms of these scores. A heterogeneous sample has a wide variation in the scores, resulting in increased values for the measures of dispersion. Range and standard deviation are the most common measures of dispersion included in research reports.The simplest measure of dispersion is the range. In published studies, range is presented in two ways: (1) the range includes the lowest and highest scores obtained for a variable, or (2) the range is calculated by subtracting the lowest score from the highest score. For example, the range for the following scores, 8, 9, 9, 10, 11, 11, might be reported as 8 to 11 (8–11), which identifies outliers or extreme values for a variable. The range can also be calculated as follows: 11 – 8 = 3. In this form, the range is a difference score that uses only the two extreme scores for the comparison. The range is generally reported in published studies but is not used in further analyses (Grove, Burns,