Marginal properties of arbitrary s-ordered quasiprobability distributi
on functions are investigated. The positivity of marginal distribution
s for an quasiprobabilities, interpolating between the Wigner function
and the Q representation of the density operator (s less-than-or-equa
l-to 0), is proven. We also show that, on the contrary, marginal distr
ibutions of the remaining quasiprobabilities, interpolating between th
e Wigner function and the P representation (s > 0), can take on negati
ve values. General formulas for the marginal distributions are given,
and their relations to the actual quantum-mechanical probability distr
ibutions for position and momentum are established. Our results provid
e an interesting generalization of some recent results concerning marg
inal properties of the P representation [G.S. Agarwal, Opt. Commun. 95
, 109 (1993)].