This package contains additional statistics classes which are not available
in the Java core library. Java only includes classes for calculating the sum
and the average of a given numeric stream (e.g.
DoubleSummaryStatistics). With the additions in this package it is
also possible to calculate the variance, skewness and kurtosis---using the
DoubleMomentStatistics class. The EvolutionStatistics object,
which can be calculated for every generation, relies on the classes of this
package.