In particular, this virtual class is defined only for internal use in the
IntervalQuestionStat package implementation since it is useful for
supplying several classes in some methods signatures. It is very important to
remark that users can not define instances of this virtual class.
See Also
Besides IntervalListOrIntervalMatrix, other virtual class defined only
for internal purposes in the IntervalQuestionStat package is
IntervalDataOrIntervalList-class.