from a /nbn/ object defining a normal Bayesian network, returns a
list comprising (i) mm
the vector of the mean of the different
nodes when the parents are nought, (ii) ss
the vector of the
conditional standard deviations and (iii) rr
the matrix of the
regression coefficients of the direct parents (rr[i,j]
contains the regression coefficient of the node j
for its
parents i
or zero when i
is not a parent of j
.