INTERQUARTILE RANGE By Nugent, Pam M.S. - May 11, 2013 Index of dispersion in a batch of scores. The difference between the 75th percentile and the 25th percentile scores in a distribution. INTERQUARTILE RANGE: "The interquartile range is an index of dispersion." Related Psychology Terms STANDARD SCORE PERCENTILE TRIMMING BIMODAL DISTRIBUTION PLATYKURTIC T DISTRIBUTION AVERAGE ABSOLUTE DEVIATION RANGE VARIANCE SKEWNESS Cite this page: Nugent, Pam M.S., "INTERQUARTILE RANGE," in PsychologyDictionary.org, May 11, 2013, https://psychologydictionary.org/interquartile-range/ (accessed September 21, 2017).