A statistical measurement of central tendency or average of a set of values, usually assumed to be the arithmetic m. unless otherwise specified. [M.E., mene fr. O.Fr., fr. L. medianus, in the middle]
arithmetic m. the m. calculated by adding a set of values and then dividing the sum by the number of values.
geometric m. the m. calculated as the antilogarithm of the arithmetic mean of the logarithms of the individual values; it can also be calculated as the nth root of the product of n values.
harmonic m. the m. calculated as the number of values being averaged, divided by the sum of their reciprocals.
regression of the m. if, for a symmetrical population with a single mode, a measurement, selected because it is extreme, is repeated, on average the second reading will be closer to the m. than the first.
standard error of the m. (SEM) a statistical index of the probability that a given sample m. is representative of the m. of the population from which the sample was drawn.
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