TRI-MEAN By N., Pam M.S. - April 29, 2013 noun. a gauge of central tendency calculated as the median's and the upper and lower hinges of the distribution of cases. TRI-MEAN: "By the time we reach our first exam, you should all know how to compute the tri-mean." Related Psychology Terms FIVE-NUMBER SUMMARY BOX PLOT CASE ALTERNATION UNIFORM DISTRIBUTION BOX PLOT SIGN TEST MIDDLE CLASS TRUNCATED DISTRIBUTION THURSTONE ATTITUDE SCALES PHARYNX Cite this page: N., Pam M.S., "TRI-MEAN," in PsychologyDictionary.org, April 29, 2013, https://psychologydictionary.org/tri-mean/ (accessed April 18, 2021).