If m_balanceType==UNIFORM_BALANCE then computes the max (values[0]) and
min (values[1]) values for each selected label and all atts if
m_balanceType==GAUSSIAN_BALANCE then computes the mean (values[0]) and
variance (values[1]) for each selected label and all atts if
m_balanceType==POISSON_BALANCE then computes the mean (values[0]) for
each selected label and all atts