Measures of central tendancy are statistical measures which describe the position of a distribution. They are also called
statistics of location, and are the complement of
statistics of dispersion, which provide information concerning the variance or
distribution of observations.
In the univariate context, the mean, median and mode are the most commonly used measures of central tendancy. They are most appropriate for unimodal distributions, but can be calculated on any series of numbers. The mode is of particular use when describing cyclical or repeating variables or when dealing with multimodal distributions.
In the bi- or multivariate context, the centroid and a number of weighted averages become useful measures of central tendancy.