A general term for several parameters related to the distribution of variables around some “central” value. These parameters are the mean, median, and mode. The median is the value at the point where exactly half the values in a set are higher and half are lower when all the values in a set are arranged in sequence. The mode is the most commonly occurring value in the set. The mean can be one of three kinds: the arithmetical mean is the sum of all the values in a set divided by the number of values in the set; the geometric mean is calculated by adding the logarithms of all the values in the set, dividing by the number of values, and taking the antilogarithm of this number; and the harmonic mean is the sum of the reciprocals of the values in a set, divided into the number of values in the set.
Subjects: Public Health and Epidemiology.