In statistics, the long tail is the large number of occurrences far from the “head” or central part of a distribution of popularities, probabilities or such. A probability distribution is said to have a long tail, if a larger share of population rests within its tail than would under a normal distribution. A long-tail distribution will arise with the inclusion of many values unusually far from the mean, which increase the magnitude of the skewness of the distribution.

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